Our team of meteorologists
have been up to something big.
And although California is in
the middle of a severe drought,
climate change is increasing the
risk of a catastrophic flood.
And this summer a report came out
warning that a disastrous mega
flood is coming to California.
Our meteorologists have been interviewing
the state's top researchers for months
and asking what is a mega flood?
What damage could it do?
And are we ready?
So tonight,
Rob Carl Mark kicks off our week
long series and he's taking a look.
The history of flooding in Sacramento
and what could happen next.
All of our tools were tough.
March on the water.
It looks like a bomb went off
there. Imagine the biggest
storm you've ever been through.
He had to chainsaw his
way out his front door.
Cold, hard rain has local
creeks and rivers running high.
All this came underneath the doors.
What if the rain didn't stop?
A levee breaks your neighborhood
starts taking on water.
In Sacramento region alone,
there's over
514,000 people that are protected
by these levies. Studies
suggest that Sacramento is actually
one of the top ten in the nation's most
at risk for flooding due to rivers.
The most intense atmospheric
river storms are likely to become
significantly more intense,
and certainly the spillway incident
was one of those instances where
did not have time. Are we prepared?
This is megaflood.
When it started raining in November,
people sort of took notice.
Dance winters coming early and
then right before Christmas,
the storms really hit.
For folks living in California in 1861,
then 1862, this wasn't a bad dream,
it was their nightmare and their
life and livelihood was washed
away and they're proceeded to be
continual rain for 43 to 45 days.
The storm started with a heavy cold.
No, followed immediately by very warm
rain that washed down all that snow. Sean
Turner is a guide that takes visitors
in Old Sacramento back to this time
and place of the Great Flood. And
to do this you have to go down
way down to the underground
where the city was originally
built. Because of that heavy
amount of water and debris coming
down out of the hillsides,
that Levy was no match for the
American River breached the levee
approximately where business 80 is now.
The water then came in and.
Flowed behind the city,
Sacramento was inundated and
annihilated by the biggest flood
they had ever recorded here.
Now, as the story goes, life must go on,
and in the middle of the great flood
we had to swear in a new governor.
His name was Leland Stanford,
and he lived right here
in downtown Sacramento.
He had to climb out of his second
story into a rowboat to get
to the capital to be sworn in.
The water would remain here
for the next three months,
an unbroken stretch of water
for more than 250 to 300.
Miles.
We're standing next to the foundations
for the Hastings building, Benjamin
Franklin Hastings and Company building.
This building has been lifted
up up to the current level.
This is a 500 ton brick
building that was one of the.
Hundreds of buildings that were
lifted over a 13 year span to
lift the central business district
up out of the floodwaters.
Since the Great Flood of
California and the lifting
of Sacramento. We haven't yet
seen the water rise that high,
but we know there will be another time.
As chaotic as California weather can be,
it's also consistent.
And history tells us well before
we could document it that these
floods happen every 100 years or
so, and more are coming. The
confidence of catastrophe casting
lies in our understanding of the
main ingredient of these floods,
atmospheric rivers or AR's. And
atmospheric river is
literally a river in the sky.
It's just a river of water vapor
moved by the wind, rather than
terrestrial river which is liquid
moved by gravity. Marty Ralph is an
expert on atmospheric rivers and says
calling these ribbons of moisture
a river is not an exaggeration.
In fact, it might be understating
California's primary source.
Of water. An average atmospheric river
transports the equivalent of like 25
Mississippi rivers worth of water.
It's vapor. When that hits shore or
hits the mountains, it's forced upward,
and some of that can condense into cloud
and rain and snow in vast quantities. 40
to 60% of California
water comes from a R's.
If you get less than you expect,
you're in a drought.
More and you flood. Much
of the research lately is focused
on forecasting atmospheric rivers,
especially the Super high.
Ones that can break the flood banks.
The Great Flood was the blueprint
for a mega flood scenario called
the Arc Storm Project back in 2011. A
collaboration of more than 100
scientists and officials at the time,
it was the best understanding
of the worst case scenario.
The report was sobering to say
the least. A cycle of major
atmospheric rivers would, quote,
overwhelm the state's flood protection
system. It would also prompt evacuations
for more than a million people and cause
nearly a trillion dollars
in damage three times.
The damage of a major California earthquake.
In short, a flood of this magnitude
is California's biggest threat.
Also, just like that earthquake,
we know it's coming.
Except the future with mega
floods is likely to be worse.
Doctor Daniel Swain is a climate
scientist at UCLA and co-author
of Essentially Arc Storm 2.0.
What does a megaflood look
like in our warming climate?
Well, he found that these storms
are now twice as likely to happen
in any given year right now,
and in the future,
we can expect two to four times more runoff.
And flooding potential then we have
historically ever observed they're warmer.
And this ends up being a really critical
aspect in the Sierra Nevada in particular
because not only are you seeing atmospheric
rivers that bring more water overall,
but more of that water is falling as
liquid rain rather than frozen snow. The
report has brought our history with
mega floods back to the future and
understanding that California's
other big one is coming and we
need to be ready.
Wow, that's a lot to take in. It is, it is.
I do want to be clear though,
when is this event expected
to happen or do we know,
right? You know, I think that's sort
of the the glaring alarm bells go
off when you see something like that
because everyone that we talked to is so
confident that it is going to happen.
But I would just rest assured a little
bit forecasting has come a long way.
We would have weeks and months of
this kind of pattern knowing we were
starting to get into the danger zone.
But there's a couple of things that
they learned that really tipped
them off most of the mega.
Floods in the past happened during
an El Nina El Nino episode.
And when they model it out in the future,
that's what they're seeing.
So that's one place to look.
But you just gotta take it month
by month and see where we are.
And just knowing that we are in
line for something like this,
that it could happen here,
I think sets everybody apart.
Just having that knowledge.
But we will have a warning.
So that's good news?
Yes.
Anything about this study surprise you at
all? I think what surprised me is
that if you ask are we prepared,
are we ready for this?
They will say in their own version. Not yet.
We need to get things done quickly.
We need to get it done
sooner rather than later.
If we wait too long,
that's just more time that's wasted.
So I think that surprised me is
that they feel like there are
still a lot of work to be done.
But the good news and we
visited some of these projects,
the work is getting done and
they're planning for the future.
So the best minds in California
know about this. They're on it.
They're working toward it.
They're building for this event.
The question is,
is when it actually happens,
are we there yet?
And then this is just the beginning of
the series. We have the whole week,
we're going to be covering mega floods.
So tomorrow Monica's her story is running,
right? The closest that we've come
to a true catastrophe related to
flooding recently was when the
spillway of the Oroville Dam broke.
So Monica is going to talk more
about that event and how it sort
of gives a bellwether about how
things may play out in the future.
Alright, Ron, thanks so much.
We appreciate it.
And our mega Mega Flood series
runs all this week right here
onto the point, so don't forget.
For more information about
what a flood could look like,
be sure to visit us online at
abc10.com slash to the point.