Big storm a big boost for #water supplies, but caution flags remain — @DenverWater #drought #snowpack #runoff

Doors across the Denver metro area opened to a scene like this as the city’s fourth-biggest snowstorm on record officially dumped 27.1 inches at Denver International Airport. Photo credit: Denver Water.

From News on Tap (Todd Hartman):

Weekend blizzard a bounty for Denver, farmers and foothills, but not a drought-buster.

The weekend storm that brought heaps of badly needed wet snow to Denver, the foothills and the plains is an important boost to water supplies, but doesn’t appear to be a full-fledged “drought-buster.”

To put it in terms of a much-anticipated upcoming college basketball tournament: The weekend’s water results were like winning the first-round of March Madness. A nice thrill, but still a few wins short of a title.

Snow, snow, so much snow, everywhere you looked. Photo credit: Denver Water.

But let’s stay optimistic for a moment. The storm was a big victory, and here are a few reasons why:

  • It’s a big recharge for soil moisture across the Denver region, and will mean a big boost for lawns and landscapes in the metro area. Overall, the storm was officially the fourth-largest ever for Denver, with an official snow depth of 27.1 inches as recorded at Denver International Airport. That’s not too far behind the 30.4 inches that fell in November 1946, which sits in third place, and the memorable pileup of March 2003, at 31.8 inches.
  • Blizzard? Bah! It’s playtime! Hardy Denverites head out for some urban cross-country skiing during the March 2021 blizzard. Photo credit: Denver Water.
  • For Denver Water, the storm was especially helpful to Gross Reservoir in its North System, where surrounding areas clocked in at 20 to 30 inches. Some of Denver Water’s lower reservoirs, including Marston, Chatfield and Ralston also will reap rewards.
  • The moisture content of the snow was unusually high, giving everyone more bang for the buck. In short, a single storm brought the same level of water some places would typically get in a month or even two months. One Denver-based meteorologist said Monday that, with this storm, Denver has recorded 4.24 inches of liquid this year, the wettest start to a calendar year on record.
  • The suburbs northwest of Denver clocked in at 24 inches of snow before the sun came out and the melting commenced. Photo credit: Denver Water.
  • Farms and water users in northeast Colorado will benefit, and that’s a benefit to Denver Water. That’s because with downstream reservoirs on the South Platte filling, it will allow Denver Water to access its water rights sooner, without having to pass as much water down the river right away.
  • “All in all, this was an extremely helpful storm,” said Nathan Elder, water supply manager for Denver Water.

    “We see benefits all around. While it wasn’t a drought-busting storm — it didn’t hit the West Slope hard and didn’t get into the upper South Platte region — it’s a great recharge for Denver and the foothills and puts us in a much better place than we were a week ago.”

    A rain gauge at Water Supply Manager Nathan Elder’s house registers the amount of water in the snow about halfway through the March 2021 blizzard. Photo credit: Denver Water.

    Even so, caveats remain.

    Despite the windfall, Denver Water’s collection system remains below average for snowpack, at 94% in the Colorado River Basin and 97% in the South Platte.

    And Colorado is coming off a very dry year, with a dry spring and a monsoon-less summer compounding an ongoing deficit in soil moisture.

    That matters because thirsty soil gets first dibs on melting snow. Water must replenish the ground before it slides down the hills and winds up in streams, rivers and reservoirs.

    It’s a snow dragon? More than two feet of snow transformed landscapes before skies cleared following the March 2021 blizzard. Photo credit: Denver Water.

    That means Denver Water, along with water utilities across Colorado, will keep watching the skies for more storms to keep us wet through the rest of March and April, a period that is generally a good bet for snow and rain. Areas along the Continental Divide and upper reaches of the West Slope — the headwaters — sorely need a wet spring.

    The message to customers: Enjoy the bounty, but don’t let down your vigilance. Residents will need to continue being smart about irrigation. Denver Water’s standard summer watering rules take effect May 1, with watering limited to three days a week, and no watering between 10 a.m. and 6 p.m.

    And it’s still possible further watering limits could be in play, depending on how the next several weeks play out.

    Clearing a path through the snow after the March 2021 blizzard. Photo credit: Denver Water.

    A spike in temperatures that rapidly depletes the snowpack, for example, could have an impact on how we use water this summer.

    For now, it’s certainly a storm worth enjoying and appreciating, while keeping it in a healthy context.

    As a March Madness coach might say, “We’re excited as heck to make the tournament … but we’re still facing an uphill climb.”

    Thank you, Mother Nature. We appreciate and value your gift. Photo credit: Denver Water.

    From KUNC (Luke Runyon):

    This weekend’s snowstorm will likely translate to significant drought relief for portions of Colorado, while others remain mired in drier than average conditions.

    The National Weather Service estimates that areas of Colorado’s northern Front Range and northeastern plains received between 2 and 4 inches of liquid water in the form of heavy, wet snow, with some localized areas receiving more than 4 inches.

    Snow that blanketed the northern Front Range and northeastern plains will provide two to three inches of liquid water when it melts. Some localized areas are seeing even higher amounts ranging from four to five inches of water held in the snow, said Colorado’s assistant state climatologist Becky Bolinger…

    The city of Burlington, for example, recorded nearly three inches of precipitation in 72 hours over the weekend. In a normal year, Burlington averages a total of 2.78 inches for the period of November through March…

    Much of Colorado’s Front Range has been locked in severe drought since August 2020. Bolinger expects the next U.S. Drought Monitor, released weekly on Thursdays, to show a contraction of severe drought on the Front Range and northeastern plains.

    The Western Slope, the part of the state in the most need of added moisture, is unlikely to see any drought relief from this storm, Bolinger said.

    From Colorado Public Radio (Sam Brasch):

    As Colorado digs out from the recent blizzard, each heavy shovel full of snow proves the storm brought plenty of moisture. But is it enough to free the state from its drought conditions?

    Russ Schumacher, the Colorado state climatologist, said the answer largely depends on location. The brunt of the storm hit east of the Continental Divide, dumping around two feet of snow in the Foothills and Eastern Plains. Meanwhile, preliminary snowfall reports show only a few inches accumulated on the Western Slope.

    Colorado’s drought conditions had improved ahead of the storm. After record dry weather over the summer and fall, snowpack levels had inched toward normal throughout the winter, but western Colorado continued to miss out on the snowfall. According to the U.S. Drought Monitor, about 16 percent of the state faced the most extreme category of “exceptional drought” as of last week. The entirety of the area was west of the Continental Divide.

    Colorado Drought Monitor March 9, 2021.

    Karl Wetlaufer, a hydrologist from the Natural Resource Conservation Service, said the weekend storm brought the entire state to 91 percent of its median snowpack for mid-March.

    Wetlaufer said soil conditions could also affect Colorado’s downstream water users. Last year’s dry weather left the ground so parched it could absorb large amounts of snowmelt. Wetlaufer said that could decrease runoff levels by as much as 20 percent, meaning the recent snow could stay in Colorado rather than flowing down the Colorado River to Las Vegas or Los Angeles.

    The recent snowstorm also likely won’t change a longer trend toward drier weather in the Southwestern U.S. A 2020 study in Science suggests the region is experiencing its worst “megadrought” since the 1500s due to global climate change. Any shift against the pattern would require a series of far wetter winters across the region…

    Nevertheless, Schumacher said it’s hard to see the recent storm as anything other than good news.

    “It may not be enough to get us out of the drought completely, but it’s going to be a big help,” Schumcher said.

    From CBS Denver (Shaun Boyd):

    Any snow is welcome snow in moisture-starved Colorado, but even two feet is too little to bring us out of the drought. Almost the entire state is in some stage of drought and more than half the state is in a severe or exceptional drought.

    “What we’re going to see from this week is a possible incremental improvement from those really bad drought categories to not-as-bad drought categories,” said Assistant State Climatologist Beck Bolinger.

    The biggest beneficiaries, she says, will be crops on the eastern plains and lawns in the Denver metro area. Denver is now 20 inches of snow above normal for this date and the city has already received four and a quarter inches of liquid.

    That is well above the average. The snow could also help delay wildfires on the Front Range.

    However, Bolinger says, it still may not stop cities from imposing watering restrictions, and more than a dozen are considering doing so. She says it’s not only about how much snow falls, but where it falls.

    “Our water municipalities are closely focused on what’s happening west of the divide in terms of replenishing water supplies that we rely on,” she said.

    The problem, she says, is the Western Slope didn’t get as much snow. Western basin averages, she says, are still 10-20% below normal.

    Even an average snowpack in the mountains may not be enough says Ben Livneh with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder.

    “The landscape is dry. When the snow melts, the first thing it has to do, it has to recharge some of that dryness, some of that deficit before it can runoff and become part of the water supply.”

    From The Ark Valley Voice (Tara Flanagan):

    Winter Storm Xylia accomplished, for the most part, what all the talk was about, becoming the largest two-day storm on record for Denver and the fourth-biggest snowstorm since 1881. Dumping heavy, wet accumulations up and down the Front Range over the weekend, the blizzard halted traffic on the interstates, knocked out power to thousands, and hit a few places especially hard – including 27.1 inches at Denver International Airport, 40 inches near Red Feather Lakes, and 30.8 inches for Cheyenne, Wyo.

    Here in Chaffee County, it was a stout storm, but as of Monday morning it was sunny, the lower areas were melting down significantly and Highway 285 was mostly dry through the mid-county after plowing efforts.

    The great news was that, according to Open Snow, Monarch Ski Area received a beastly 24 inches (11 on Saturday and 13 Sunday) – the same total as Wolf Creek. Further west, Telluride took bragging rights from the storm with 27 inches. Elsewhere it was hit or miss: Mid-Vail reported a scant 6.

    Xylia delivered some good gains to the state’s snowpack. Portions of the Arkansas River Basin – which includes Chaffee County – saw some of the biggest action from the storm, putting the basin’s snowpack at 99 percent of average, compared to 90 percent recorded March 11.

    Westwide SNOTEL basin-filled map March 16, 2021 via the NRCS.

    According to the USDA’s SNOTEL water snow-equivalent reporting systems, the Upper Rio Grande basin is now at 104 percent compared to 98 percent. Percentages in Colorado’s other basins include: South Platte, 97 (was 87); North Platte, 96 (was 90); Yampa and White, 91 (was 88); Upper Colorado, 88 (was 84); Gunnison, 85 (was 81); and the southwest mountains including the San Miguel, Dolores, Animas and San Juan river basins, 81 (were 78).

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