Replenishing the Rivers and Reservoirs

paddle boarder on an alpine lake

By Jonathan Thompson

No one who spent any time in the Four Corners region between Christmas and Easter needs a magazine article to tell them it was a whopper of a winter. Snow really began piling up in the San Juan Mountains in late December and, except for a bit of a pause during the typical January thaw, it never really stopped. By late March, Colorado high country’s denizens were downright fed up with shoveling the white stuff, and some were even tiring of day after day of freshies and face shots.

But even the folks who had to dig themselves out of their homes several times during winter and spring might be wondering how this water year compared to those of yore. Was it as abnormally abundant as it seemed? Or did it just look big next to the string of meager snow years that together added up to the most severe dry spell of the last 1,200 years? And what does all that snow piled up on the mountains mean for the drought? Can we safely say it’s over?

We’ll get to that. But it might be helpful to first look back forty years to the epic winter (and spring) of 1982-83 to which all other water years will be compared—especially in the Colorado River Basin and the San Juan Mountains. If you lived through it, you’ll never forget. If not, here’s a recap.

Winter started early that year in some areas. The La Sal Mountains near Moab saw significant snowfall beginning in late September, and by early December Lizard Head Pass had twice the normal snowpack for that date. As is often the case, however, December and even much of January were virtually precipitation-free—a relentless parade of bluebird days and chilly nights, rotting away the snow and creating a deep level of depth hoar, anathema to backcountry skiers and snow safety professionals.

Then El Niño, characterized by warming Pacific Ocean waters, crashed the party. Normally, trade winds—the tropical winds near the Earth’s surface—blow west along the equator, moving warm Pacific Ocean water from the Americas toward Asia. This cycle is disrupted every two to seven years by El Niño-Southern Oscillation, or ENSO, events, which typically last about a year. During El Niño, the winds weaken, and warm water is pushed back toward the Americas. La Niña, by contrast, strengthens trade winds and brings cool water to the surface of the Americas West Coast.

For the Southwestern U.S., El Niño years are typically wetter and cooler and La Niñas drier and warmer—with exceptions. An especially robust El Niño churned up the Pacific’s waters in 1983, and the effects were acute here. Snow piled up in the mountains to depths not seen since the early 1950s. The Colorado River Basin-wide snowpack finally peaked in late May, several weeks later than normal. Then temperatures shot up suddenly, accompanied by heavy, snow-melting June rain that put nearly every stream and river in the region well above flood stage.

The San Miguel River near Uravan hit 8,050 cubic feet per second that May, the biggest spring runoff on record by far (although it did hit 8,900 during the huge flood of Sept. 1970). The Dolores River topped 6,000 cubic feet per second near the town of Dolores; while not a record, it’s only come close to that level twice in the last forty years. More dramatic events were happening downstream in the Dolores River Canyon where an estimated 8,000 cubic feet of ice-cold, roiling, chocolate milk-hued water was crashing over and around the giant boulders of Snaggletooth Rapid every second.

A procession of kayakers and rafters lined up to test their mettle in the raging waters. Most made it only a bit worse for wear, though they must have been tired from bailing those big old boats. A handful of rafts flipped, their ejected occupants forced to swim the remainder of the long rapid before getting themselves to shore. And at least two rafts got wrapped around the Snaggletooth itself, one of them seemingly inextricably, though the video—released by Rig to Flip several years back—doesn’t show what happened to those unfortunate floaters.

Further downstream things were even scarier. Caught off guard by the deluge, Glen Canyon Dam’s operators had not left enough room in Lake Powell to contain the sudden surge of Colorado River inflows, which reached 120,000 cubic feet per second—about ten times the volume of an average spring runoff. With water literally lapping at the crest of the dam, operators opened the left spillway for the first time ever, sending a massive volume of water into the Grand Canyon. For a day or two, all seemed fine. Then, the innards of the spillway tunnel started deteriorating, spitting Volkswagen-sized boulders into the river bed.

In the end, the spillways were fixed and the dam survived. But 1983 will forever go down as the year of the big snows, the Glen Canyon Dam close call, and the last year the lower Dolores River would run free. McPhee Dam started impounding water later that year.

Runoff Redux

Last fall, southwestern Colorado prepared for yet another dismal winter. La Niña—the dry yin to El Niño’s yang—was back for a rare, third consecutive year. The previous two winters had fit the usual La Niña pattern, with scant winter snowfall melting off and evaporating during unusually warm spring days, robbing high country ski areas of snow, turning forests into kindling, and depriving lowland ditches and farms of critical irrigation water, which devastated crops and opened the door to grasshopper plagues of Biblical proportions.

There was no reason to expect that 2022-23 would be any different. But this time, La Niña had a wet and cool surprise up her sleeve, blessing most of the West with a relentless parade of snow- and rain-laden atmospheric rivers.

The snow-removal industry boomed, roads shut down due to flooding and avalanches, power outages were rampant as heavy, wet snow toppled trees and utility lines, and virtually every backcountry road in southern Utah turned into slippery-as-snot muddy luge tracks that could challenge even the most burly off-road vehicle. And every bit of it was a soothing balm to the drought-weary land.

But with abundance also came tragedy. In northern and central Arizona the sometimes dry Oak Creek and Verde River turned into raging torrents, forcing mass evacuations. Two hikers were killed by flash flooding in a southern Utah canyon and a third had to be rescued by helicopter. At Purgatory Resort north of Durango, a roof-alanche careened off a building and buried a father and his two children, leaving all three in critical condition. The five-year-old girl later died from her injuries.

As of early April, many weather stations in the Four Corners recorded as much as two times the normal amount of moisture in the snow for the date, often setting records in the process. But not all of the Natural Resources Conservation Service SNOTEL stations, which are the most reliable way of comparing snowpacks from year to year, were set up yet in 1983, so direct, region-wide comparisons are hard to come by. Still, a close look at the data offer some comparisons, such as:

  • Mesa Verde National Park weather station recorded 4.34 inches of precipitation in March 1983 compared to 4.03 inches in March 2023;
  • The Lizard Head Pass SNOTEL station had 20.6 inches of snow water equivalent (SWE) on April 2, 1983 and 23.2 inches on April 2, 2023. 
  • The La Sal Mountain SNOTEL station had 24 inches SWE on April 2, 1983 and 25 inches on April 2, 2023;
  • And the Dolores River Basin SNOTEL stations recorded 24.5 inches SWE on April 2, 1993 (previously the biggest year on record) and 28.7 inches on April 2, 2023. 

In other words, there was a s&$t ton of snow blanketing the region in early spring, maybe even more in most places than there was in 1983. Temperatures shot up in mid-April, and the mountain snowpack—a giant natural reservoir for the Dolores, the San Miguel, the San Juan, and the Colorado Rivers—began melting. The frigid water trickled then roared down high slopes to fill up rivers and reservoirs below, a boon to boaters, irrigators, hydropower users and water managers. After months of hand-wringing and teeth-gnashing over the prospect of Glen Canyon Dam losing hydropower production capacity or even reaching the dreaded dead pool, the Bureau of Reclamation is now predicting this winter’s bountiful snowpack will be enough to fend off further water level declines through 2024. 

McPhee Reservoir is full again, guaranteeing that the same farmers who watched ditches run dry over the past two summers will receive their allocated shares of water this year. Plus, dam managers were able to release enough water to the lower Dolores to make Snaggletooth runnable once again, though it was still only a shadow of its pre-dam days. The big water is also, for better or worse, easing some of the urgency behind efforts to cut Colorado River water consumption to sustainable levels. The Western drought is far from over, but it certainly has subsided: Two years ago nearly 60 percent of the region was in severe, extreme or exceptional drought; now it’s down to 16 percent, and Arizona is nearly drought-free. 

Of course, it will take more than one good year to really end the drought and heal the land and trees. And more than that to fill Lake Powell and Lake Mead back up to their capacity. But who knows, it may actually happen: Meteorologists are predicting that next winter will be an El Niño year. And you know what that means … .