Heavy rain has little impact on Utah drought
Aug 2, 2021, 5:48 PM
(Scott G Winterton, Deseret News)
It would be an understatement to simply say ‘it has rained a lot over the past few days.’ Some areas have experienced flash flooding, while others are above average for rainfall at this point in the year.
“We’ve finally seen a strong monsoonal surge coming up from the southwest,” said Glen Merrill, a hydrologist with the National Weather Service Salt Lake City office. “Utah’s more often than not on the fringe of that, but this year we’ve been right under the gun.”
Amazing amounts of rain yesterday! pic.twitter.com/eo6pNl1Q94
— Grant Weyman (@KSLweyman) August 2, 2021
Unfortunately, it’s not enough
However, that rain is localized and not widespread enough to pull Utah from the exceptional drought. It is essentially too sporadic to make a dent. Sunday is a prime example.
“At the airport, we picked up 0.18 inches of rainfall,” says Merrill. “On the east bench, we received 1.5 inches during the same time period.”
The rain has helped in some ways and the overall drought conditions have improved slightly. Merrill says the precipitation has revived the soil to some extent and lessened demand on the state’s water supply.
On the other hand, the majority of the recent rain cannot be absorbed. It rapidly runs off and does not enter the state’s water supply system.
Weather forecasts call for more pockets of heavy rain with the possibility of flash flooding Monday, but another spell of dry and warm weather is around the corner.
Just received a report of flash flooding in Grand Wash in Capitol Reef National Park. #utwx
— NWS Salt Lake City (@NWSSaltLakeCity) August 2, 2021
How much rain to erase the Utah drought?
The bulk of Utah’s water supply, more than 90%, comes from snowmelt runoff and storage. Merrill says we need more consistent rain over broader areas of Utah to improve from this drought — but our best chance for precipitation on that scale comes in the winter. Snowfall between October and the following May represents the next cold season. Merrill says it will need to be above-average.
“That’s where we’re going to need to see a dent moving forward. We’re probably going to need several above-average winters to catch up from the deficit that we’ve accrued over the last few years,” Merrill predicts.
At the start of August, it is a little too early in the year to start looking for signals regarding the 2021/22 winter expectations.
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- Bountiful flood control measures mitigated damage from Sunday’s storm