Heavy downpours are on the rise across the entire United States—even in arid parts of the country. Bernadette Woods Placky gives us some reasons why the saying “when it rains it pours” is truer now than it ever has been.
MoreA plume of moisture from the tropics is bringing potent and deadly rains to California and the Southwest. On Monday evening, flash flooding killed eight in southern Utah. On Tuesday morning, Angelenos and other residents of Southern California awakened to what’s shaping up to be one the wettest September days on record.
Monday’s heavy rain arrived in southwest Utah courtesy of a strong plume of moisture associated with the monsoon. Roughly three-quarters of an inch of rain fell in the high reaches of Zion National Park.
When siphoned through the narrow canyons in and around the Park, that seemingly small amount of rain created a wall of water and debris that tore downstream. A river gauge operated by the Colorado River Basin Forecast Center shows the flood surging down the East Fork Virgin River around 6:30 p.m. local time on Monday.
The river rose almost 9 feet in the span of an hour. Photographer AJ McCrea was in Zion when the floodwaters rose. In his post on Instagram, he said, “40 minutes ago toddlers could have been safely playing in this stream.”
The flood eventually reached Hilldale, Utah, a small city on the border with Arizona. A river gauge in Colorado City, Ariz., located adjacent to Hilldale, shows flood levels peaked at over 6 feet. The slurry of water, dirt, trees and rocks swept across streets and left eight dead and five others missing.
Rain is likely again today and tomorrow as another blast of moisture takes aim at the Southwest, keeping flood risk elevated. That rain will come courtesy of the remnants of Hurricane Linda, which is currently parked over Los Angeles with near record-setting results.
A chart showing the peak of the flash flood on the East Fork Virgin River in southern Utah.
Hurricane Linda had a short but exciting life in the tropics. The storm formed last Sunday, attained Category 3 status on Tuesday as it skirted along the Baja Peninsula and fell apart by Thursday. But tropical storm or not, Linda’s remnants have their act together enough to bring drenching rains to Los Angeles.
The city has seen 2.4 inches of rain downtown as of 8:30 a.m. local time. That trails only Sept. 25, 1939, when 3.96 inches of rain fell, as the wettest September day on record for the city. September is usually the tail end of the dry season for Los Angeles and the city receives just 0.24 inches of precipitation on average for the month.
While it remains to be seen if Tuesday will take the all-time September rain record, one thing is clear: this is the most rain Los Angeles has seen in awhile. Tuesday is the wettest day Los Angeles has had in three years. The last time the city saw this much rain is when 2.42 inches fell on March 20, 2011.
That lack of rain is what has Los Angeles and California as a whole in the middle of one of the state’s most epic droughts. Forty-six percent of the state is mired in exceptional drought, which is as bad as it gets according to the U.S. Drought Monitor, and more than 97 percent of the state is experiencing some form of drought.
Last winter’s snowpack was the lowest the Golden State has seen in at least 500 years. The dryness is a major driver for increased wildfire activity across the state, including the Valley Fire, which has burned 67,000 acres in Lake County and is only 15 percent contained. Recent findings suggest that up to a quarter of the drought can be attributed to manmade climate change and rising temperatures.
There’s hope that the burgeoning El Niño could help bring drought relief to parts of the state. But it’s unlikely to alleviate it completely. And any heavy rain that does fall in the state could actually wreak more havoc by causing mudslides and erosion as it falls on parched, rock-hard soil.
Precipitable water in the eastern Pacific, including the pattern bringing heavy rain to Los Angeles on Tuesday
