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How much water would it take to get out of this drought?

Posted at 3:46 PM, Jul 15, 2021
and last updated 2021-07-15 18:46:34-04

LAS VEGAS (KTNV) — It’s going to take much more than a monsoon to even break the surface of coming out of our current drought.

Stanford University professor and senior fellow Dr. Noah Diffenbaugh explains, "Think about it like if you didn’t get paid for three months and then your employer gave you a normal paycheck and said okay now we are back to normal. Well, you’re back to normal for that paycheck but you’re not back to normal for those three months."

High elevation snowpacks are well below normal for much of the Western states and snowmelt is the number one driving force in keeping water reservoirs full.

National Weather Service meteorologist Barry Pierce told us: "We’re not seeing the typical snowpack in the winter season. This generates most of the run-off which fills the reservoirs. People can assume that if we get a lot of rain that will fill the reservoirs but that’s going to take a lot of rain."

Previously, Lake Mead reached historic lows with the ongoing threat of water shortages.

Most of our region's precipitation comes in the form of snow and when we experience snow droughts, there are devastating economic, environmental and social impacts.

"We have greater flood risk during the wet times because that snowpack is less reliable. It also means we have less water supply in the dry times because that snow is not there in the same quantities," said Diffenbaugh.

As global and local temperatures rise, less of that precipitation drops in the form of snow and high winds can cause snow to evaporate.

"This year was actually forecast to be the third-lowest run-off for the entire Colorado River basin," Pierce stated.

The old saying of "Too much of a good thing can be bad" applies during the monsoon as on the surface substantial rainfall would be a good thing but too much rain doesn’t allow the surface to absorb it, increasing the risk of flash flooding.

"When it comes to intense rainfall, the soils in the Mojave Desert can’t infiltrate the rainfall fast enough. Most of that occurs in run-off which will then lead to flash flooding," says Pierce.

The National Weather Service says while we will take any rain we can get since we headed into last winter so dry, most of the rain we will get will go towards replenishing soil moisture, not our water supply.

"This monsoon may only contribute less than 5 percent of the overall run-off for the reservoirs," said Pierce.

That’s why we count on more snowfall up in the Colorado and Utah mountains.

"What we are experiencing in the west is not just a lack of precipitation but the accumulated effects of loss of reliability of snowpack, drying out of soils and drying out of vegetation. We’re in a state of extreme drought," says Diffenbaugh.

Climate models are predicting the occurrence of snow droughts to occur more frequently as the climate continues to change.