Water levels plummet across West

We did receive some welcome rainfall last week, but conditions here in North Idaho and the rest of the western U.S. are still very dry.

As of Saturday, about .30 inches of rain had fallen in Coeur d’Alene this month. June’s normal precipitation is 1.93 inches, so based on current patterns, it looks like we’ll have a fourth straight month with precipitation totals below normal in North Idaho.

Long-range computer models are continuing to show a strong high pressure system locked in over the western states. Over the next several weeks, little if any moisture is expected across the West, including the Inland Empire. However, there's a chance of some showers or a few thunderstorms during the full moon cycle of June 24.

Since Jan. 1, Cliff has measured slightly over 11 inches of rain and melted snow in northwestern Coeur d’Alene. The normal for the season to date is near 13 inches.

It’s been extremely dry at Spokane International Airport. Less than a tenth of an inch has fallen thus far in June with a seasonal total of less than 4.50 inches. The airport is currently sitting at about 50 percent of normal moisture.

Despite the stretch of drier-than-normal weather across the Inland Northwest, reservoir levels are still good. As of June 1, reservoir capacity for Idaho is around 80 percent, which is slightly less than average for this time of year.

In Washington, the reservoir capacity is approximately 79 percent, about 3 percent below normal. In Montana and Wyoming, water levels are reported as being above average.

Unfortunately, the rest of the western states are seeing their rivers, lakes, wells and other sources of fresh water drying up. In Nevada, the average reservoir capacity in early June is around 62 percent. The latest reading is at 37 percent.

It’s even worse in New Mexico as the state average is currently at 20 percent of capacity compared to a normal of about 47 percent. Oregon is barely over 50 percent reservoir capacity as conditions have been very dry over the last few months.

In California, the massive two-year drought has sent water storage levels to less than 50 percent. Many cities are considering new conservation plans for water restrictions and farmers have been forced to scale back on plantings due to the lack of water.

A large percentage of Californians depend on seasonal snowpack in the Sierra Nevada Mountains for water. Back in March, the snowpack was about 50 to 70 percent of normal. However, the recent big warm spell led the snow to either be evaporated or soaked up by dry ground, resulting in reduced runoff. The lack of water has led to drought emergencies being declared across the state.

It’s almost hard to believe that two years ago, the snowpack in the Sierra Nevadas was over 200 percent of normal in the early spring. But this drought year was the worst since the massive one back in 1977. In fact, soil moisture levels — water that is in the upper portion of soils — is at the lowest levels in history across many areas in the West.

It’s also the driest or second driest conditions across most southwestern stations since the late 1800s. Many scientists and state officials are declaring that the West is in a “megadrought” with not much relief expected in the near future.

The main source of water for over 40 million people in the Southwest is from the Colorado River. The largest reservoir on the river is Lake Mead, about 35 miles outside Las Vegas. It was formed by construction of Hoover Dam in the 1930s, and thanks to a long-term drought that has lasted for decades, water levels have steadily declined.

Lake Mead is sitting at one of its lowest water levels. It’s currently near 37 percent of capacity and the water level is expected to decline further over at least the next four months.

In addition to supplying fresh water to residents in the Desert Southwest, Hoover Dam also provides electricity for parts of Southern California, Arizona and Nevada. As lake levels drop, output of electricity from the dam goes down as well.

This very low water level may lead to a declaration of Colorado River water shortages from the federal government.

For the best chance of above-normal rainfall in the Southwest, we usually need to see a moderate to strong El Nino, the warmer-than-normal sea-surface temperature event in the waters of the south-central Pacific Ocean. Right now, we’re in the middle of the cooler La Nina and warmer El Nino with a La Nada, and little change in this pattern is expected at least into the fall season.

However, a few forecast computer models are suggesting that a new El Nino may form next year.

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Contact Randy Mann at randy@longrangeweather.com