JOHN YANG: A massive heat dome has been# spreading across much of the United States,## with temperatures reaching historic highs, but# it's not an isolated spike.

In recent weeks,## the country has grappled with a# series of extreme weather events.

Ali Rogin more for our# periodic series Tipping Point.

ALI ROGIN: John, this heat is not just notable for# nearly unprecedented early spring temperatures,## but also for the amount of ground it's# covering.

Temperatures have been 20 to## 40 degrees above normal in the Great# Plains, and it's been moving east.

Some cities are already seeing record-breaking# streaks, and the heat is expected to last into## early April.

That's because a high-pressure# system is acting like a lid, trapping hot air## underneath and allowing temperatures to rise day# by day.

The Southwest registered triple digits,## with temperatures reaching# 101 degrees in New Mexico.## Kansas also set a march record with# 102 degrees twice in four days.

For more on what we can expect in the coming days,## I'm joined by Bernadette Woods Placky,# chief meteorologist at Climate Central.

Bernadette, thank you so much for being here.

How unusual is it for us to see this type of# heat in March, and has this ever happened before?

BERNADETTE WOODS PLACKY, Climate# Central: This is wildly unusual.

And,## no, it has not happened to this level before.

I do think people are used to# seeing temperatures spike 100## degrees in Phoenix and Las Vegas, but that's# usually May, June, July.

It's not in March.

ALI ROGIN: And how far has this# heat spread in the country so far,## and what can we expect in the coming days?

BERNADETTE WOODS PLACKY: Sure, so there's a# lot of ways to put together these numbers, and,## any way you look at them, they are breaking# records like we have never seen before.

One is, we broke an all-time temperature# record for March for the country.

We also## have had multiple states break their# all-time March temperature record.

We## have seen hundreds of records a# day happen over this past week.

And when you break down the balance# of record highs to record lows,## we took it back all the way to the# beginning of the year, because,## remember, there were some cold stretches.

But# since the beginning of the year, 85 percent of## our records have been warm or hot records,# and only 15 percent have been cold records.

So there's a lot of coverage# in that early season cold.## It's nothing compared to what# we're experiencing right now.

ALI ROGIN: So you mentioned we're# seeing record heat, record cold,## but why is it that we are seeing# more record hot weather than cold?

BERNADETTE WOODS PLACKY: Well,# that's because of climate change.

Now, one is the weather pattern.

It's# extraordinary for this time of year.

It## looks more like a weather pattern we'd see# in July.

But that weather pattern alone,## combined with the additional fossil fuel# pollution we put into our atmosphere,## is why we're breaking records to this level.

And one way you can look at that, right,# is, we understand the greenhouse effect.## This is science that goes back to the# 1800s that really isn't challenged.

And## we can measure those greenhouse gases in the# atmosphere, and we know we're putting more of## those into our atmosphere from the burning# of fossil fuels like oil, coal, and gas.

So when you thicken that blanket around our# atmosphere, it traps more heat.

The most obvious## and direct way that we experience that extra# warming on our planet is through extra hot days.

ALI ROGIN: And, now, we have been# experiencing these heat domes.

For## the last 10 years, they have been on# the rise.

What makes them different,## though, from just other types# of early spring warm weather?

BERNADETTE WOODS PLACKY: Well, we have had## heat domes before.

We .. But what happens underneath those, when you add# those extra greenhouse gas in the atmosphere,## it allows our temperatures to go to levels# we have never experienced.

So that's the## big difference right now, is that every time# we're using the word unprecedented or record,## and it feels like it's getting# a little old to some people,## but it's happening that frequently right now# that we're pushing record highs to this level.

ALI ROGIN: This hot weather is also# having implications for things like## snowpack and water resources out West.# How is this going to affect communities## not just in the present,# but in the months to come?

BERNADETTE WOODS PLACKY: This is a really# important part of this conversation,## because the West as a whole has been# really low on its amount of snow this year.

And you got to remember that's water.

That's# water for the warmer months.

That's how we water## our plants and our crops.

That's also our water# resources.

So, on April 1, this is a really big## day out West, where we take these measurements# across many different areas in the mountains and## get an assessment of where that snowpack is for# the year as we head into these warmer months.

We are so low.

We're at record lows.

And# it really varies from state to state.

But## it's not only that it's record# low.

This March heat has forced## melting earlier than usual.

So we're not# going to have that water in the same ways## at the times that we need it.

And then# that really ups our risk for wildfire.

ALI ROGIN: The weather just seems# to get worse and worse every year,## but it's not just extreme heat.

It's# also things like flooding in Hawaii,## rare snow in Alabama, shifting# temperatures in the Northeast.

What else can we expect in terms of# extreme weather for the rest of this year?

BERNADETTE WOODS PLACKY: Well, it's# interesting to look at this as a full pattern.

One thing we do know is that we are shifting# into what's called an El Nino year.

And there## have been discussions of this in the past, and# people have followed along.

But what happens## during El Nino years is, we get this extra# boost of heat in the water that translates## into our atmosphere, and it usually pushes our# temperatures overall for the planet higher.

So that is one thing.

And then that shifts# our weather patterns a little bit more.

But## what we also know is that, when you add more# heat to this atmosphere, it's like a boiling## pot of water, right?

And so things get more# turbulent.

And when we have more rain events,## when they do actually trigger, there's# more precipitation for them to come down.

And when we get these heat events, it# pushes to higher levels.

And that's## what we're experiencing right# now.

And that will continue.

ALI ROGIN: In the 40 seconds we have left, I# want to ask you about these floods in Hawaii## that seem to be really unusual.# What can you attribute that to?

BERNADETTE WOODS PLACKY: Well,# one way we have looked at that## is the water temperatures.

These are# islands.

And the storms are coming off## of the water.

And the water around the# islands right now is higher than usual.

And there is a climate change fingerprint in# that also.

And we can look at that through## what we call attribution science, and# we can tease out that role of climate## change in those water temperatures.

So it's# adding more fuel and more moisture for these## storms.

It's adding an extra little boost to# the already wet pattern that was setting up.

ALI ROGIN: Bernadette Woods Placky with Climate# Central, thank you so much for joining us.

BERNADETTE WOODS PLACKY: Thanks for having me.