Okay, let's unpack this. For those of you who
regularly track climate shifts and infrastructure
planning, you already know how critical long
-range weather data is, but what happens when
the most advanced tool we have, designed specifically
to give us foresight into our rainfall future,
I mean, a system crucial for protecting lives
and property, what happens when that's suddenly
put on ice? Welcome to the Meteorology Matters
podcast. Today we're taking a deep dive into
something that while it really touches every
single community across the United States, how
we predict extreme rainfall, especially now as
our climate is, let's face it, rapidly shifting.
We're talking about the fundamental science that
lets us prepare for dangerous flood events, and
importantly, a groundbreaking program that was
really poised to revolutionize that preparation.
Until it wasn't, we're going to explore what
this vital project, known as Atlas 15, was meticulously
engineered to achieve. And, maybe more importantly,
precisely why its most crucial component, the
part that looks squarely into our future rainfall
risks, has been, well... inexplicably halted.
You're going to hear why leading experts believe
this decision could leave entire communities
dangerously vulnerable, especially with the escalating
number of severe floods we're already seeing.
This isn't just about, you know, numbers on a
chart. It's about safety. It's about resilience
and frankly the staggering cost of inaction.
So let's set the stage. What exactly is Atlas
15 and why is it considered so incredibly important
for the safety and the long -term planning of
our communities. That's really the foundational
question, isn't it? What's truly groundbreaking
about Atlas 15 is how it's designed. It's meant
to be the definitive source, spatially continuous,
for understanding precipitation frequency across
the entire United States. Spatially continuous,
so like... covering everywhere. Exactly. Think
of it as this unparalleled national map. And
it doesn't just show you how much rain might
fall, but precisely the statistically expected
amount for any given storm duration. So that
could be anything from a quick five -minute downpour
right up to, say, two months of continuous rain.
60 days. Wow. Yeah, at any specific location
you can imagine. And it's not about vague possibilities.
It's about the precise probability of an event
happening, like, you know, a 20 % chance chance
that a certain rainfall amount will be exceeded
in any given year. OK, so it gives planners actual
odds to work with. Precisely. And this represents
a truly monumental upgrade from our current standard,
which is called Atlas 14. Right, Atlas 14. I've
had that mentioned a lot in engineering context.
Oh, absolutely. For decades, Atlas 14 has been
the steadfast bedrock. Civil engineers, regional
planners, they've all relied on it. It guides
the design of everything from essential drainage
systems to massive city infrastructure projects.
Its data really underpins countless critical
decisions that affect our daily lives, our safety,
the very foundation of our built environment.
So for decades, that's been our guiding star
for planning. But now with our climate changing
so fast, it sounds like that star is Well, it's
moving, isn't it? And we definitely need a new
map. Absolutely. That's a great way to put it.
The core insight here, the real sort of paradigm
shift with Atlas 15, is its move away from what's
called a stationary assumption. A stationary
assumption, meaning? Meaning it assumes the climate
is stable. That extreme precipitation events
don't significantly change over time. For decades,
we designed things as if the climate were static.
Imagine building a house for, say, 20th century
weather and just assuming it would never fundamentally
change. Which we now know isn't true. Exactly.
But Atlas 15, for the very first time at this
national scale, would account for future temporal
trends in rainfall all the way through the year
2100. It embraces a non -stationary assumption.
Non -stationary. OK, so it builds in the fact
that things are changing. Precisely. Think of
it like this. A stationary approach is like predicting
future traffic based only on today's patterns.
OK. A non -stationary approach, which Atlas 15
embraces, means you're also factoring in that,
say, the number of cars on the road is growing
every single year. So you predict, based on future
traffic, not just what's happened before. That
makes sense. You have to account for the trend.
Right. And that foresight is absolutely crucial
for planning resilient infrastructure. And what
we know is a rapidly changing climate. The science
has advanced. equivocally acknowledge that past
patterns are no longer a perfect predictor of
future risks, especially with warming global
temperatures? That's a huge leap in thinking,
isn't it? It means we're no longer just predicting
weather in the short term, but predicting the
impact of climate change on weather, specifically
rainfall, decades out. And this wasn't just some
like academic side project, right? This is a
federally funded, broadly supported effort. Exactly
right. It's important to note that the United
States Congress, specifically through the bipartisan
infrastructure law, actually provided the National
Oceanic and Atmospheric Administration, NOAA,
with direct funding to update Atlas 14 and, crucially,
develop Atlas 15. NOAA's own Office of Water
Prediction is developing it, with contributions
from a really vast array of experts across government
agencies, private industry, academia. This isn't
some small, isolated project. It's a monumental
collection. collaborative scientific endeavor
backed by federal law and broad expertise. So
Alice 15 sounds like the essential tool we desperately
need, especially for a future with more extreme
weather and escalating flood risks. But it's
not quite that simple, is it? Things got complicated.
We understand Atlas 15 was intended to be released
in two distinct volumes. Can you break those
down for us? What do they entail? And where do
things stand now? Absolutely. It was intelligently
envisioned in two parts, volume one and volume
two. Volume one provides a comprehensive snapshot
of current precipitation estimates. It meticulously
accounts for temporal changes and historical
observations right up to the present day. When
it's published, this will significantly update
and supersede the existing Atlas 14 data. So
it brings us up to date based on recent history.
Okay, so Volume 1 is like the modern version
of Atlas 14 using the latest historical data.
Pretty much. In that part of the project, Volume
1 is still on track. Preliminary estimates for
the contiguous US are expected to be available
for peer review this year, 2025, and then published
estimates by 2026. So that alone is a valuable
update for planners and engineers working with,
you know, contemporary conditions. OK, that's
good news at least. But then there's volume two.
Right. And here's where the true foresight and,
well, the unexpected twist in this story comes
in. Volume two is where the real forward looking
capability resides. This volume was ingeniously
designed to provide model based precipitation
frequency estimates projected directly into the
future. Okay, so that's the non -stationary part
in action. Exactly. It takes the robust current
estimates from Volume 1 and then applies these
sophisticated adjustment factors based on downscaled
climate model data. Essentially, it was built
to show us, in granular, actionable detail, how
rainfall risks, the frequency, the intensity
of storms, how those will evolve in a warming
world, peering decades into the future to help
communities not just react but proactively prepare.
And this Volume 2, the one that tells us about
future risks, that's the part that has been stopped.
We've heard conflicting reports about why. What
exactly happened to this crucial component? That's
correct. Work on volume two, specifically Atlas
15's climate projections, has been put on indefinite
hold for months now. According to reports, this
decision came after a review of volume two was
ordered this spring by Commerce Secretary Howard
Litnick, who is an official appointed by the
Donald Trump administration. OK, so a review
was ordered by the Commerce Secretary. What was
the official reason given? Well, a spokeswoman
for the National Weather Service speaking on
behalf of NOAA confirmed the delay. The statement
was that the review is about making sure research
dollars and technology investments are being
put to the very best use for the American people.
Maximizing resources. But you mentioned conflicting
reports. Yes, because former federal officials
who were intimately familiar with the project,
they offer a different perspective. Ed Clark,
for instance, he was the director of NOAA's National
Water Center until recently. He noted that the
research for Volume 2 was actually nearly complete
before he retired in April. Nearly complete that's
what he stated and he explicitly emphasized that
the remaining work wasn't a large price tag Implying
that cost wasn't really the primary barrier or
perhaps shouldn't have been so we have these
two narratives an official statement about maximizing
resource use ensuring taxpayer money is well
spent and on the other hand Experts like Clark
saying the work was almost done wasn't that expensive
and is incredibly vital From your perspective,
what could be the potential arguments for initiating
such a review, even if the research was nearing
completion? And how do experts weigh those against
the warnings we're hearing about losing this
critical data? That's a really crucial point
of contention. You could argue from a purely
administrative standpoint that any new leadership
or even existing leadership under a particular
administration might want to review ongoing projects,
you know, to ensure alignment with their priorities,
perhaps scrutinize the methodology, maybe evaluate
the underlying climate models for robustness,
even if the scientists involved are confident.
Due diligence, they might call it. Okay, so a
standard procedural review, potentially. Potentially.
However, experts like Clark are weighing that
against the, frankly, immense public good this
data promises. They argue that halting a nearly
complete project, one that's described as relatively
inexpensive at this stage and one with such profound
implications for public safety and fiscal responsibility,
well, it simply doesn't seem to align with the
idea of best use of resources. Right. The urgency
seems to be a major factor for them. Absolutely.
The urgency of climate change impacts, which
we're seeing daily, makes any delay and crucial
foresight deeply concerning. Regardless of the
stated intentions behind the review, the question
really becomes whether a review is genuinely
about optimizing things or if it inadvertently
or some might argue intentionally hampers progress
on climate sensitive projects like this one.
That definitely makes the situation even more
perplexing. So, OK, let's get down to brass tacks
here. What is this indefinite suspension of volume
two? mean for us, for the general public? If
we lose this crucial future projection, what's
the real tangible impact on our safety, our communities,
and ultimately our wallets? This raises an absolutely
vital question. And the answer is quite stark
and immediate. We are not talking about hypothetical
future problems, not at all. These are current
escalating threats that impact communities right
now. The toll of intensifying storms is already
painfully apparent across the country. Just look
at the first 15 days of July this year. The National
Weather Service reported double the usual number
of flash floods. Double. That's significant.
It's huge. And this wasn't just a statistic.
It included tragic delusions, like in central
Texas, that claimed over 130 lives. Heavy rains
in the Northeast drowned two people in New Jersey
severely submerged New York's subway stations,
paralyzing parts of the city. These aren't isolated
anymore, they're becoming horrifyingly more frequent,
more intense. And without the forward -looking
data that Atlas 15 Volume 2 promised, communities
are, frankly, tragically struggling to keep up.
It feels like we're constantly reacting, not
preparing. Exactly. And consider this alarming
reality. Communities across the country are still
relying on rainfall data that is decades old
to determine their flood risks and design their
infrastructure. Decades. Decades old. In this
rapidly changing climate. Yes. Imagine trying
to navigate a rapidly changing, unpredictable
road ahead by looking only in your rearview mirror.
That's essentially what we're doing without these
future projections. Without Atlas 15 Volume 2,
there will be no single authoritative national
data set to show how rainfall and flood threats
will undeniably increase as the world warms.
This creates a dangerous and, frankly, expanding
knowledge gap for absolutely crucial long -term
planning. It leaves us blindsided by events that
we could and really should anticipate. And even
Volume 1, the updated historical data, might
not be enough. Well, Jeremy Porter, who leads
climate implications research at the First Street
Foundation, he highlights that critical point.
Even volume one, which uses historical data,
he says, will be out of date very quickly because
rising global temperatures are just so profoundly
and rapidly altering precipitation patterns.
Right. The underlying system's changing too fast.
Exactly. The physics are clear. They're undeniable.
A warmer atmosphere simply holds more moisture
that provides significantly more fuel for extreme
storms. His team's analysis found that a staggering
20 percent of the U .S. has already seen a fourfold
increase in the likelihood of what used to be
considered a one in 100 year rainfall event.
A fourfold increase for one fifth of the country
already. Already. And these once rare events
are now expected to become even more common.
Turning what we thought of as once in a lifetime
floods in to much more frequent, devastating
occurrences. So it's not just about bigger storms.
It's like our whole definition of extreme is
being rapidly rewritten, and our current plans
just aren't accounting for it. What's the practical
implication of that for, say, a city engineer
trying to design a bridge or a culvert? Precisely.
It's a moving target, and they're aiming based
on old information. Ed Clark, the former NOAA
official we mentioned, he explicitly stated that
delaying or cancelling Atlas 15's climate injections
could leave communities dangerously unprepared
for these shifting flood risks. He stressed that
it makes it significantly harder, maybe even
impossible sometimes, for engineers to properly
design buildings, bridges, road culverts, all
sorts of vital projects, to design them to cope
with future rainfall extremes that are no longer
theoretical, but, uh... And he linked it to cost
savings, didn't he? He did. His summation was
powerful, I thought. He said, designing our infrastructure
for resilience is fundamentally a cost -saving
measure. When we don't design for these future
conditions, we are essentially guaranteeing that
we'll have to pay far more later, often repeatedly.
To repair or replace severely damaged infrastructure,
it drains taxpayer dollars and massively disrupts
lives. That really puts it in perspective. It's
not just about the initial cost, but the long
-term cost of not preparing. Exactly. And Chad
Brigennis, he's the executive director of the
Association of State Floodplain Managers. He
emphasizes this point, especially for you, the
taxpayer. He points out that city and state regulations
and the civil engineers designing critical infrastructure,
they aren't just encouraged. They're often required
to consult NOAA's data. And these projects, you
know, bridges, dams, drainage systems, they're
meant to last 50 years, maybe even more. 50 years
or more built on potentially outdated data. That's
the risk. So without these future projections,
Brigidus asks us to think about it. infrastructure
that simply wasn't designed for the weather conditions
climate change is bringing. The cycle of damage
and repair. Precisely. His conclusion is crystal
clear. If we have this future information we
won't have to continue to be in the cycle of
damage, repair, replace, damage again. This isn't
just about scientific accuracy. It's about fundamental
fiscal responsibility and the basic well -being
of every American community. That's a very stark
reminder of the financial and human cost. And
wasn't there even concrete evidence of this impact
from areas that did get a glimpse of this forward
looking data? Right. A pilot program. There was,
yes. Which makes the suspension even more frustrating
for many observers. A pilot version of Atlas
15 was done for Montana, and it did include future
projections. It showed that rainfall rates for
what were once considered one in a hundred year
events could increase significantly on the current
warming path. This is an abstract theory. It's
tangible data for a specific region. And what
about other vulnerable areas? Well, flood -prone
regions like the Northeast and Appalachia, they
are expected to experience even greater increases
in extreme rainfall. But without Volume 2 being
completed and released, those states won't know
the exact extent of these critical changes. They're
left planning, essentially, flying blind. Planning
for a past climate that, quite simply, no longer
exists. It's like knowing there's a storm coming,
but having no idea if it's just a drizzle or
a Category 5 hurricane. This is a truly sobering
picture. Okay, let's shift gears slightly for
a moment, though it's all connected. Let's zoom
in on the cutting -edge science that was being
developed for Volume 2. What exactly are we talking
about when we discuss tools like iMURG and these
hybrid models? And what capability are we actually
missing out on by not having Volume 2 move forward?
Absolutely. It's important to understand the
sophistication here. The research we're discussing,
leveraging something kind of integrated multi
-satellite retrievals for global precipitation
measurement. IMERG. IMERG, exactly. It's precisely
the kind of advanced science that would have
fed directly into Atlas 15 Volume 2. IMERG is
really a next -generation satellite -based precipitation
product. It's incredibly sophisticated. It doesn't
just collect data from one satellite, but combines
data from various satellite sources and then
crucially it rigorously calibrates that data
with extensive global ground observations rain
gauges on the ground. This multi -source, validated
approach gives it an incredibly high degree of
accuracy and reliability for precipitation estimates,
especially across vast regions where ground data
might be sparse. Okay, so it's pointing together
the best of space -based and ground -based data?
In essence, yes. And the study we're looking
at introduces a novel hybrid PDF model for estimating
what are called depth duration frequency curves,
DDF curves, using this IMERG data. DDF curves.
Remind us what those are again. Right. DDF curves
are basically the precision blueprints for engineers
and hydrologists. They tell you exactly how much
rain depth is expected over a given time duration,
say, one hour or 24 hours. And critically, how
often frequency that kind of event is likely
to occur maybe once every 10 years, or once every
100 years, or even more rarely. This data is
the absolute bedrock for designing everything
from storm drains and culverts to bridges and
skyscrapers, ensuring they can handle the expected
rainfall without failing. Got it. So these DDF
curves are the vital numbers engineers need.
How does this new hybrid model improve on how
we get those numbers? Well, the true brilliance
of this hybrid model isn't just about using more
data, like from IMERG, but its inherent intelligence,
if you will. This model integrates no less than
four four different probability distribution
functions. Okay, probability distribution functions.
Yeah. Those are the math formulas. Exactly. They're
just the mathematical formulas or models that
help us predict the likelihood of different rainfall
amounts happening. The probability of getting
two inches in an hour versus five inches, for
example. Now, why is using four of them so important?
Because no single mathematical model works perfectly
across all climate zones. A formula that's great
for, say, the rainy Pacific Northwest might not
be the best for the arid southwest. Ah, so different
climates need different math. Essentially, yes.
What this hybrid approach does is it dynamically
adjusts its weights. How much importance it gives
to each of those four individual mathematical
models based on the specific local climate conditions.
This optimizes the rainfall estimates for both
wet regions and dry regions, making the predictions
much more accurate and precisely tailored to
specific geographies, that's crucial for real
world applications. So it adapts itself depending
on where you're looking. Precisely. And the study
rigorously showed that the DDF estimates derived
from IMERG using this hybrid model aligned very
strongly with the existing Atlas 14 data, where
we have good ground truth from over 2 ,300 stations
across the contiguous US. This validation isn't
just a detail. It powerfully demonstrates its
robust capability for continental scale extreme
precipitation analysis. It's not just a theoretical
concept. It's a proven, high -performing tool
ready for prime time. That sounds like a significant
step forward in accuracy. It is. A key innovation
here is that this hybrid model gives us a much
better way to understand how precipitation extremes
actually vary with climate zone and wetness conditions.
That's a major improvement over relying on just
one single model of for everywhere. And its adaptability
to climate change projections is absolutely key.
Remember, those projections predict not only
increases in extreme precipitation, but also
significant shifts in patterns. Right. Things
might get wetter overall in some places, but
maybe the rain falls in shorter, more intense
bursts, for example. Exactly. So, for instance,
in high precipitation areas, like the eastern
US, where heavy, prolonged rains are common,
the model might determine an optimal equal weighting
for its components to capture those events accurately.
But then, in drier, western areas, where maybe
flashier, shorter -duration intense events are
more critical, it intelligently adapts. It might
give more weight to the mathematical models better
suited for those specific conditions. This capability
means significantly more accurate extreme precipitation
forecasting tailored for very different regional
needs across the country. That kind of regional
precision sounds incredibly valuable. It moves
away from a one -size -fits -all approach to
something that genuinely understands the nuances
of different climates. Were there any limitations
or biases identified? I mean, it's pretty common
in complex modeling like this, right? Absolutely,
and it's important to acknowledge them. Understanding
limitations is just part of robust science. The
research did identify some biases, which is normal
and expected. For example, IMERG tends to slightly
underestimate rainfall in some of the drier western
regions, particularly for shorter duration events,
and it might slightly overestimate in some wetter
eastern areas, especially for longer durations.
Okay, so there are known tendencies. Yes, but
these are well understood biases. The crucial
point is that because they are understood, they
can be accounted for. They can be further refined
through ongoing research and calibration. These
aren't fundamental flaws that undermine the model's
overall utility. They're known quantities that
engineers and planners are actually trained to
work with. Knowing these biases allows them to
apply precise adjustment factors in their designs,
ensuring real -world accuracy. So the biases
are known and manageable. Correct. And this kind
of precise, regionally adapted predictive analytics
is truly essential for developing effective climate
adaptation strategies. It directly supports better
flood risk management. It leads to improved and
more resilient infrastructure planning. It even
enables more effective ecosystem conservation
in areas most vulnerable to climate -induced
extreme weather events. Plus, the ability to
seamlessly integrate this kind of model with
machine learning techniques further amplifies
its potential. It allows for continuous learning
and improvement in forecasting accuracy over
time. It's like a living tool that learns and
gets better. It certainly sounds like the science
is not only ready, but really capable of providing
the nuanced, forward -looking information our
communities desperately need to face a changing
climate. It seems, then, that the suspension
of Volume 2 could really lead us to inadvertently
or perhaps deliberately ignore these critical
insights into our changing climate, potentially
leaving communities much more vulnerable. That's
a profound implication. It is. It essentially
means we might be consciously choosing to operate
with an incomplete picture of our future risks,
despite having the scientific capability right
here, right now, to paint a much clearer one.
So, to try and tie all this together, we've explored
ALICE -15, its immense promise to help us foresee
future rainfall extremes, and the really groundbreaking
science, like IMERG and the hybrid models, that
was driving it forward. Yet, the critical volume
2, The part designed specifically to give us
those absolutely vital future projections that's
been indefinitely suspended following a review
ordered by officials in the Donald Trump administration.
And as we've heard, this isn't just about scientific
data, as important as that is. It seems deeply
connected to the safety of our homes, the long
-term resilience of our roads, bridges, cities,
our infrastructure, and of course the massive
escalating costs we continue to face from ever
-increasing flood events across the country.
That's right. Without these authoritative future
projections, communities are really left trying
to build and plan with an incomplete picture.
They're relying on outdated assumptions in a
world that is fundamentally and rapidly changing
around them. The consequences are tangible. We
see them in the news. More frequent and devastating
floods, higher repair costs for taxpayers, and
most tragically, more lives put needlessly at
risk. The ability to predict these future conditions
using advanced tools like the IMERG hybrid model.
It sounds less like an academic exercise and
more like, as you said, a taxpayer -saving, even
life -saving imperative. Many experts would certainly
argue that. So the decision to halt this work,
to pause this progress, it means that we as a
nation are potentially less informed and consequently
far more vulnerable to the accelerating impacts
of climate change that we know are happening.
As you or listeners go about your day, maybe
consider the floods we've already seen just this
July alone. Think about the mounting costs of
rebuilding both financially and emotionally for
the communities affected. Now just imagine for
a moment if our communities actually had that
authoritative forward -looking data that Atlas
15 Volume 2 promised. What fundamental changes
would we make? In our infrastructure, our zoning
laws, our emergency preparedness plans, what
devastating disasters could we potentially avert
or at least mitigate significantly? That's something
truly worth mulling over. Thank you for joining
us on this critical discussion for the Meteorology
Matters podcast. It's certainly given us a lot
to think about. For more insights into the world
of meteorology and how it impacts all our lives,
make sure you follow meteorologist Rob Jones
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