Lead Timmer seizes a rare opportunity to get a glimpse of how powerful flash floods begin

From rivulets of water flowing between rocks in arid, barren mountainside landscapes to roaring rivers in just minutes, the southwest monsoon floods escalate rapidly. Every summer, extreme meteorologist Reed Timmer best known for tracking tornadoescontinues the “Flash Flood Chase”, which aims to capture the moment when rainwater transforms a parched landscape into a perilous wall of water.

A dramatic video recently shot by Timmer north american monsoon Began in earnest in early August Wilhoite, Arizona, a town just north of Phoenix. The fast waters quickly created roaring rivers in the Arizona desert landscape.

As Timmer explains, it’s amazing to see these “flash flood interceptions” pull off, and many people watching these videos may end up asking: I can’t.

“I have always been interested in small-scale meteorology such as tornadoes, lake-induced snow and flash floods, but I love the hybrid atmospheric and geographic approach to tracking flash floods,” said Timmer of AccuWeather. said in an interview. “Also, you need all your senses. You can often hear a flash flood approaching minutes before it arrives.”

In the southwest, states such as Arizona and New Mexico typically rely heavily on the monsoon season for annual rainfall and are dry most of the year. Accuweather Meteorologist Alex DaSilva explains:

The dry, hard-cracked land and lack of vegetation in the Southwest make it nearly impossible for water to be absorbed into the ground, and it often runs off when it rains. Even heavy rains can cause life-threatening situations.

“Flash floods can come on very quickly. The southwest usually doesn’t get as much rain as the eastern regions, so even a small amount of rain can cause flash floods,” DaSilva said.

Timmer captured a rarely seen moment last week. The arroyos (dry riverbeds) in this area were rapidly filling with streams of water that seemed to have no end in sight.

Water down Arroyo in Wilhoite, Arizona. (Extreme Meteorologist Reed Timmer)

A flash flood front wall is formed as the water flows down the newly formed riverbed, created in a matter of seconds in front of the timer’s camera.

These arroyos and slot canyons carry this fast-moving water miles away from where the storm originated. This can affect areas that don’t get much rain and threaten hikers unfamiliar with the weather.

“I use rainfall data from radar and target storms that have even the slightest apparent spin in the radar reflectance,” Timmer explains. “This means they’re causing a lot of rain, releasing the thermal energy stored in the water molecules and spinning the storm a bit.”

Timmer told AccuWeather in 2018 when it first started tracking floods in the Southwest.debris plug.”

When Arroyo hasn’t been submerged for a while, it’s usually filled with a lot of debris, Timmer said. Soil friction slows the movement of the debris plug and intensifies flooding behind the plug.

“We also target areas with old burn scars from previous wildfires because they can flood much more easily and there are often debris flows and debris flows along the flood front wall.” said Timmer. “Debris gives flash floods even more destructive power.”

In a video he shot in 2018, You can see the debris plugs that hold back the strong water flow.His video is a reminder not to underestimate the power of fast-moving water. An afternoon outdoors or a canyon hike can quickly turn into a life-threatening situation.

“It’s all about patience and waiting for the flood to come,” Timmer said. “The surface here in the Southwest Desert doesn’t absorb water particularly quickly across burn scars, so only about 0.75 inches of precipitation per hour is needed to produce a life-threatening flash flood.”

according to National Weather Service Floods kill more people than hurricanes, tornadoes and lightning strikes, according to the (NWS), and although flash floods are a particular type of flooding, they still cause a significant number of casualties each year.

Earlier this month, heavy rains caused deadly flash floods overnight. Eastern Kentuckysuffered over 38 casualties.

AccuWeather forecasters say these elusive videos show just how dangerous flash floods can be and emphasize the importance of paying attention to everything. weather warning and evacuation orders.

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