Las Vegas Sun

March 28, 2024

Experts warn newcomers of flash flood dangers

Flash flood control experts are reaching out to new residents, warning them of the potential dangers of a sudden summer thunderstorm that could swamp them in their homes or cars within minutes.

When black clouds tower over the mountains and valley, lightning flashes and thunder crashes, it's a warning sign that there's a flash flood on the way.

Despite 62 detention basins and about 350 miles of concrete channels that work to move floodwaters through the valley's urban areas, a 100-year flash flood swamped the northwest Las Vegas Valley on Aug. 19, 2003. The odds of such a flood occurring are once in 100 years, but a deadly flash flood can come any day in Southern Nevada.

Ted Greener and his wife, Debbie, sloshed around their home on Chardonnay Way near Rainy River Road in knee-deep water that day last August. Floodwaters even invaded their refrigerator.

It took until Thanksgiving to return their home to normal, Greener said this week. Personal items, such as family photos, will take much longer to replace.

"We're mostly recovered, but it was not the best time of our lives," Greener said. They had lived in their northwest valley home for seven years before the flood hit.

One piece of advice Greener has for new residents: check out flood insurance before floodwaters flow. After the Greener's home flooded, the premiums were too high to pay, he said.

While flash flood season normally spans July through September, flash floods can, and have, happened in every month of the year in the valley's 99-year history, according to the Regional Flood Control District.

"With more than 6,000 new residents moving to Southern Nevada each month, it is critical that we make every effort to inform citizens about the dangers of flash flooding," said Larry Brown, Regional Flood Control District chairman and a Las Vegas City councilman.

The flood safety campaign should catch motorists' attention and make people think of the devastating consequences of flash floods, said Gale Fraser, Regional Flood Control District general manager.

"More people die each year in flash floods than any other natural disaster," Fraser said. "The majority of these deaths are from motorists trying to drive through flooded areas."

Since 1960, 13 flash floods have taken the lives of a total of 26 people, affecting the homeless in particular.

One new effort in the campaign is a direct-mail warning to between 40,000 and 50,000 new residents about the flash flood season, said Betty Hollister, a Flood Control District spokeswoman. Those residents who moved here between September 2003 and April 2004 should have received the first mailing.

The next mailing is scheduled for late August for newcomers arriving throughout the summer, Hollister said. A billboard campaign will also be used to remind people of the dangers of driving in floods.

One of the most important tips to remember when black clouds signal a downpour is to make a careful decision on whether to drive or not, Fraser said.

Just a few inches of swiftly moving water can swamp a vehicle, even an SUV. Motorists caught in a severe storm should head for higher ground and wait for the storm to pass, Fraser advised.

Another danger to people and animals, especially children and family pets, caught in flash floods is water contamination. Floodwaters are filled with oil, chemicals, pet waste and other dangerous debris, often trapping bacteria and viruses.

Additionally, water running through flood channels and underground storm drains can rise as fast as one foot per minute and move as quickly as 30 mph, Fraser said. Floodwaters as little as six inches deep can sweep a person off their feet and they could be carried away and drown.

Southern Nevada officials are anxious for the Regional Flood Control District to finish its work flood-proofing the valley.

The district has spent about $900 million on the task in the past 15 years.

But it will take another 64 detention basins and 460 miles of channel built in the next 25 to 30 years to complete such a project, Hollister said. The cost is estimated at $1.7 billion.

About 18 projects are under development today.

One of them is called the Cheyenne peaking basin, a unique flood control project on Cheyenne Avenue east of Civic Center Drive, said Dennis Merrett of Diamond Construction. He is the project manager.

The channel will funnel water across the valley into the Las Vegas Wash during a small flood, but if the surge is too high, waters will back up into a detention basin that will slow down the flows across the valley.

"The project is so unique, it's been very interesting to work on," Merrett said.

The bulldozers started moving dirt at the beginning of August 2003 and workers saw the power of a flash flood later that month. "We were working in the channel when it occurred," Merrett, a three-year Las Vegas resident, said. No one was injured.

As development moves to the edges of the valley, into the foothills, natural rainfall has to run somewhere, Hollister said.

"Developers are required to build pathways through their housing developments," she said.

However, in the August 2003 flood, many of the drains were blocked. Some captured debris off the desert; others were plugged with SUVs, sheds or even homemade coverings such as mesh netting.

The valley's flood control officials believe their work is worth the effort. Since 1960 the area has experienced at least nine floods costing $1 million or more each. The July 1999 flood brought a valley-wide disaster declaration from former President Clinton and $22 million in federal aid.

In addition to pouring concrete and educating the public, the flood control district is also trying to prepare residents by helping them determine if they need flood insurance.

Flood insurance is available to every homeowner and renter, even if they are not in a flood zone, said Kevin Eubanks, assistant general manager of the Regional Flood Control District.

Typical homeowners' insurance policies do not cover damage caused by flooding, Eubanks said.

archive