Local NewsDrought Crisis


Monsoon by itself has little impact on drought

Posted at 7:20 PM, Aug 01, 2022

LAS VEGAS (KTNV) — One after the other, storms dropped flood causing water across the desert southwest. Just in this past month Las Vegas got 0.68 inches of rainfall compared to the climatological normal of 0.38 inches.

When this rain isn’t flooding roadways or going towards soil moisture, it’s flowing through the valley washes into the Las Vegas Wash that eventually flows into Lake Mead. The question is, is monsoon making a dent in the decades long drought?

The Bureau of Reclamation reported some of water from the storms made it into Lake Mead.

Civil engineer Noe Santos told us: "We were looking at what we were projection earlier in the month compared to where we ended. We are 2 and a half inches give or take higher compared to what we thought we were going to be."

Still, the water basin is only 27% full.

RELATED: Pahrump roads, Spring Mountain Motor Resort impacted by flood

Recent studies done by the Geophysical Research Letters Journal show that while monsoon contributes about 1/5th of water to the Colorado River Basin and 10% of the annual streamflow, most of the water comes from snowpack in the mountains. Streamflow is the amount of water flowing into a river.

Desert Research Institute assistant research professor and Western Regional Climate Center regional climatologist Ben Hatchett explains: "We need some snow and some summer precipitation. Those two things together can help put a dent in the drought. If we have a really good monsoon year then it’s a wetter environment. The problem is that it’s been so dry, we think we have so much water because we know how much snow we have but then we get less than we expect. That’s because of these very very dry soils."

However this water cannot fully replenish streamflow from less snowpack. The big picture for our water source is still low.

Outlooks from the study show that monsoon streamflow decreases when snowpack is low and dry conditions persist. Because of this, it’s likely the monsoon’s ability to produce streamflow will decrease in a warmer future.

The Southern Nevada Water Authority says the biggest help you can do at home is turn off irrigation systems during rain events.