Flash flooding and powerful winds hit California

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The first tropical storm to hit southern California since 1939 came and went on Monday, carving a path of destruction as it tracked north-northwest through Nevada.

Post-Tropical Cyclone Hilary is now predicted to head toward Idaho, Oregon and Montana where flood watches are in effect until Tuesday morning.

Here are a few key moments from today:

• Palm Springs, California was one of the areas hardest hit. Inches of rain turned the normally dry barren landscape into flood lands and mudflows. Roads closed, powerlines fell, and access to emergency service lines in the area ceased for hours. Thousands were without power. Emergency phone lines have now been restored.
• Las Vegas, Nevada is now in the path of the storm. A boil water notice was issued for nearby residents of Kyle Canyon. Massive floodwaters there also caused a concrete road to collapse. The rest of the state continues to endure the deluge, with a flood watch in effect until 20:00 local time on Monday in some places.
• Los Angeles, California is now in recovery mode. Downtown Los Angeles reported 2.48in (6.29cm) of rain on Sunday, making it the wettest August day in the area on record. The city opened a record number of emergency temporary shelters for its homeless population, the most "since at least 2020".

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These aerial photos give a sense of the scale of the damage caused by the sudden heavy rains in Rancho Mirage, near Palm Springs, in California.

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Mud and floodwaters have completely engulfed part of the Interstate 10 highway.

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The wettest August day on record in California used to be 46 years ago, way back in 1977... until Storm Hilary arrived.

Now, the wettest day is 20 August 2023.

On Sunday, eight cities in the Golden State received record-breaking August rainfall, according to the National Weather Service.

Palm Springs had 3.18in (8.07cm), surpassing the previous record of 2.03in (5.16cm).

And in Cuyamaca, 4.11in (10.43cm) of rain fell, well above its previous August record of 2.61in (6.63cm).

Flooding over the typically dry and barren landscape has caused mudflows, trapped cars and closed several roads.

The worst of the storm is over for Los Angeles, yet the city is still urging residents to stay home and stay safe.

Flooding and strong winds downed trees and powerlines and caused a few road closures, some of which have yet to re-open.

Los Angeles Police Department responded to 125 car crashes, according to the latest city update, though no fatal or "significant injuries" were reported.

All public schools in Los Angeles school district were closed on Monday. The city has announced more than a dozen "grab-and-go" meal distribution sites for families with students.

Los Angeles officials said the city has also opened the most emergency temporary shelters for its homeless population "since at least 2020".

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Thunderbird Country Club in Rancho Mirage, California, has been severely hit by the storm.

Mud and debris have covered parts of the greens and cut off passage across a bridge, and tree branches and pieces of wood litter the area.

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Several roads and businesses remain closed today after Storm Hilary drenched the area with record rainfall overnight.

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At the peak of the storm, residents living in Palm Springs who tried to call 911 - the emergency services line in the US - could not get through.

They were directed to text 911 or call non-emergency lines, Palm Springs mayor Grace Garner said this morning at 04:00 local time.After hours without having the ability to dial 911 for help amid the historic storm, officials have notified residents that emergency calls are now being directed to the Palm Springs Police Department call centre.

The 911 phone lines in the area are back up and running.

Cities and towns in the path of Storm Hilary are "quite vulnerable" and have soil that "cannot handle" heavy rain, according to Jamie Rhome - who oversees the National Hurricane Centre's Storm Surge Unit.

Rhome says the rain has hit areas that were previously scorched by wildfires, which meant the soil was virtually like a slick "pavement".

You can hear more from Rhome in the video below.

Climate change is in large parts responsible for this storm, says prof Kathleen Treseder, from the University of California, Irvine's Ecology and Evolutionary Biology department.

It increases the frequency and intensity of the El Niño weather phenomenon, which leads to warmer waters in the Pacific Ocean and ultimately generates suitable conditions for these storms.

"This is a 100 year storm and we're getting a lot of 100 year events here," Treseder says, adding that more events of this scope are to be expected in coming years.

"Whenever we have an extreme event like this now I tell myself this is not gonna be a one-off, likely we are gonna have more and it may even be worse," she says.

The National Weather Service has issued advisories this morning for three more tropical storms which are developing across the Atlantic and heading towards the US.

Tropical Storm Franklin is currently located over the eastern Caribbean sea.

Several hundred miles further to the east is Tropical Storm Gert.

According to the NWS, signs of showers and thunderstorms have already begun over the Gulf of Mexico.

"Tropical storm warnings or watches are likely to be issued later today," the NWS has said.

The third event, Tropical Storm Emily, is roughly 1,100 (1700km) miles west off Africa's Cabo Verde islands.

As it moves west, it may form into a storm that reaches US shores "later this week", the NWS says.

Officials warn another storm could potentially develop south of Mexico in the Pacific over the next few days and move north towards the US.

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We're now seeing more of the damage caused by Storm Hilary.

These pictures show a large eucalyptus tree which fell over last night in Sun Valley, California.

Parts of the tree crashed on to two cars parked in front of a house and damaged a metal fence.

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Several trees and power lines were toppled as winds swept across the region over the last few hours.

A number of roads also remain closed and flooding continues after the storm brought record-breaking rainfall overnight.

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US states, including Vermont, have been restoring flood plains and wetlands to increase their resistance to flooding.

Vermont has also been purchasing flood-prone properties in a bid to move homeowners to higher ground.

Texas, meanwhile, has launched a state-wide plan to assess its vulnerability to flooding and review which projects could prevent damage.

In Houston, climate-resilient homes are protecting residents from extreme flooding caused by hurricanes and storm water run-off.

Other towns, such as Valmeyer, in Illinois, have opted to relocate and rebuild in the wake of devastating floods.

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We've just heard from Sean Heslin, who lives in Palm Springs.

Here's what Sean had to say:

Tropical Storm Hilary was slow to arrive in Palm Springs but when she got here, she came with a bang.

In fewer than 12 hours, Hilary brought the greater Palm Springs area between 3-4 inches of rain, nearly one third of our annual expected rainfall. Many local roads flooded within the first hour. All our phones were buzzing with flash flood alerts throughout the day and well into the night. During the heaviest rains yesterday, many residents spent hours sweeping water away from doorways to prevent their homes from flooding.

Another concern for many residents were pools overflowing. Many folks used large buckets to try and displace pool water.

Waking up at 06:15 this morning, I saw typical bright sunshine and some beautiful cloud formations, but also multiple emails and texts from Palm Springs Police Department.

Every major road in and out of Palm Springs, including the I-10 freeway, has been shut down for 30 miles surrounding. Local police are still recommending we all stay home and off the roads.

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The rain has now stopped in Hollywood and damage has been limited to some power outages and a few downed trees.

LA fires chief, Kristin Crowley, said there were no significant reports of damage in Los Angeles and no loss of life.

The 5 freeway is gridlocked with traffic due to flooding, but in the Hollywood Hills, the situation was normal.

A handful of tourists were hiking to get a glimpse of the famous Hollywood sign, which was no longer shrouded in clouds.

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Hilary was previously a category four hurricane with wind speeds hitting 145mph (233km/h).

Since arriving on US shores, it has gone from a tropical storm to a post-tropical cyclone.

But what is a post-tropical cyclone?

Well, it's a "cyclone that no longer possesses sufficient tropical characteristics", according to the National Oceanic and Atmospheric Administration, which, among other things, means that its core temperature has dropped.

However, this does not mean that the storm has lost strength.

In 2012, Hurricane Sandy was a post-tropical storm by the time it reached New Jersey but still had 80mph (128km/h) winds and brought several inches of rain.

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Normally hot and dry, the desert town of Palm Springs was one of the areas hardest hit by Tropical Storm Hilary.

Footage shows flooding and mudflows covering the streets as abandoned cars floated in flood water.

Roads were closed and downed powerlines left thousands without electricity.

"Our 911 lines are down at the moment," Palm Springs mayor Grace Garner told NBC on this morning, adding "it's a huge concern."

The previous single-day record for rainfall in Palm Springs, recorded in 1930, was 2.03in (5.15cm).

On Sunday, 3.18in of rain fell across the dusty landscape.

After a night of epic rain and little sleep, the storm has finally gone.

We were pummelled by a relentless downpour in Santa Clarita, 32 miles (50km) north of Los Angeles, which saw record levels for a 24-hour period.

But, for the most part, the view outside is remarkably normal. It's like, "did that really happen?"

There is some flooding and road closures, but the summer heat is drying the streets quickly.

With such a vast amount of rain in what is usually the year's driest month, the events of the past few hours have created an interesting paradigm for the traditionally parched countryside.

The sun and searing heat will be back very soon.

It remains to be seen how this extraordinary event impacts the enduring wildfire season.

The weeds will grow but nothing is going to burn, at least for a short while.

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The eye of the storm has now moved into Nevada.

Several areas in the state are under flood watch warnings until Monday evening, including Las Vegas.

Flash flooding also remains a risk for the area, the National Weather Service said.

Nevada Governor Joe Lombardo declared a state of emergency on Sunday.

Throughout the day the storm is expected to continue moving north, where forecasters predict moderate to heavy rain may also create flooding.

Currently under flood watch are parts of south-east California, Arizona, Utah, Oregon and Idaho.

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"Virtually all" daily rainfall records in Los Angeles have been broken, the National Weather Service says.

The highest rainfall total was recorded in Lewis Ranch, in the mountainous region, with a total of 7 inches (nearly 18 cm) in the last 48 hours.

The highest wind gusts were 87mph (140km/h) in the area of the Western San Gabriel Mountains, recorded about 3am Monday.