California Storms: Providing Temporary Relief to Lakes Powell and Mead
As of August 2023, the storms that impacted California earlier in the year did contribute to some improvements in water levels for several reservoirs, including Lakes Powell and Mead. However, these improvements were modest compared to the overall deficits caused by prolonged drought conditions.
Water Levels and Drought Conditions
Located on the Colorado River, Lake Powell and the largest reservoir in the U.S., Lake Mead, have been experiencing significant declines in water levels due to long-term drought and increased water demands. While winter storms and spring runoff in 2023 provided some relief and temporarily helped raise water levels, the overall situation remains critical. Any gains are often offset by evaporation and ongoing water usage.
Atmospheric Rivers and Their Impact
Yes, these “atmospheric rivers” of subtropical Pacific moisture slamming into California also extend rainfall across the Southwest. The storms bring higher levels of snowfall in the Rocky Mountains than seen in the last few years. This additional snowpack in the mountains is a positive development, as it means there is potential for better water supply in the coming spring when the snow melts.
The Long-Term Outlook and Challenges
Lakes Powell and Mead are located in Nevada, Arizona, and Utah, to the east of California. While storms hitting California can eventually affect these states, the region is generally a desert environment due to the rain shadow effect of mountain ranges in California. This means that wet weather in California may or may not translate to wet weather in surrounding states like these.
The lakes are primarily fed by snowmelt from the southern part of the Rocky Mountains in Colorado, Utah, and portions of New Mexico and Wyoming. Fortunately, snowpack in most of these mountain regions is now well above normal. However, this won't help the lakes until the snow melts in the spring. Rainfall in desert areas below the mountains mostly sinks into the ground, but a portion will run off into the reservoirs.
Despite these positive developments, the two reservoirs are so depleted that a tremendous amount of water is needed to bring them back to a reasonable level. A single good winter may help them a bit, but they need more wet winters to start to substantially recover.
In summary, while the California storms did contribute some water to these lakes, the long-term outlook depends on sustained precipitation and effective water management strategies across the region.