LAS VEGAS (KLAS) — It’s been more than two weeks since the atmospheric river caused destruction in California — and brought optimism about a building snowpack in the Rockies.
But with a couple of “patchy snow” days and nine “warm” days in the extended 14-day forecast for the Colorado Rockies, the snowpack could be shrinking soon. A U.S. Bureau of Reclamation page that displays snow water equivalent (SWE) levels for the Upper Colorado River Basin is something to watch over the coming weeks.
Currently, the SWE level is at 142% of normal for the entire Upper Basin, which includes mountain ranges in Colorado, Wyoming, Utah, northwest New Mexico and northeast Arizona. That’s good news, but it has shrunk from 153% on Jan. 19.
Snowmelt feeds the Colorado River, filling reservoirs along the way to Lake Mead and canals that deliver water to Arizona and California. Even if snowmelt produces above-average river flows this year, the level of Lake Mead is expected to keep dropping as the government fills Lake Powell and other reservoirs in Colorado, Utah, Wyoming and New Mexico.
Negotiations between water officials in states that depend on Colorado River water produced an agreement on Monday between all the states except California — which came up with its own plan for the river. The federal government is expected to decide how to proceed on the states’ recommendations.
But all the agreements currently favor keeping water in Lake Powell. If they don’t do that, it threatens electric power produced at Glen Canyon Dam. If Lake Powell drops below that level, it might not be able to release enough water to meet demands downstream in Nevada, Arizona and California.
That approach has frustrated some conservationists who have suggested that Glen Canyon Dam is a problem that should be dealt with sooner than later.
Eric Kuhn, former general manager of the Colorado River District, said in December that “revolutionary change” is needed. He suggested the facility could be converted to a flood control dam, putting an end to producing hydropower.
Snowpack in the Upper Basin usually hits its peak in early April.
Watching snowpack levels is a lot like watching the weather — there are no guarantees. And climate scientists have found that the 23-year drought has changed the game. More water is lost to the thirsty ground before it ever reaches the river, and that trend is expected to continue.
Here’s a look at how the snowpack level has changed over the past month. (The blue “Upper Colorado” label tells the average for the entire Upper Basin, next to the snowflake symbol):
January was the eighth snowiest month in Colorado in recorded history.
March and April are typically the snowiest months in Colorado, where the headwaters for the Colorado River start. The mountains around Rocky Mountain National Park (“Colorado Headwaters” on the map) are critically important in the river’s water supply.
The percentages displayed on the map are relative to what’s “normal” — the average on a given day over the past 30 years. So if snowpack goes up 10 inches tomorrow, but snowpack normally goes up 20 inches on that date, the percentage would go down.
Climatologists are watching to see if the La Nina weather pattern — in its third-straight year, a rarity — follows past patterns and brings dry conditions to the Rockies in the coming months.
According to the Colorado Basin River Forecast Center, the April through July snowmelt runoff is expected to swell the river to 117% of its 30-year average as that snow melts and runs downstream to Lake Powell. In December, that forecast had dipped as low as 79% of average.