EVANSTON — Senior Service Hydrologist Glen Merrill from the National Weather Service in Salt Lake City recently spoke to an audience of county personnel during an April 3 Uinta County Local Emergency Planning Committee (LEPC) meeting, held at the Emergency Operations Center (EOC) room in the basement of the Uinta County Complex.

“You guys are just in great shape from a hydrologic standpoint,” Merrill said. 

Merrill explained that the county is still reaping the benefits from the last couple of winters, most notably due to the well-above-normal snow conditions.

“It was a very warm winter ... pretty much all states in the west were above average temperature wise, Uinta County specifically,” he said, stating that the southwest corner of the state landed in the top tenth percentile for warmest year on record in 2024.

From a precipitation standpoint, the north slope of the Uintas, according to Merrill, received above average snowfall.

“But there hasn’t been nearly enough snow at the lower-level elevations,” he said.

Merrill said the current weather pattern for the year has been a “La Niña pattern,” a colder weather pattern that increases and strengthens trade winds, jet streams and upwelling.

“The storms coming from the north slope, banking into the Uintas ... can draw out a lot more snowfall or precipitation,” he said.  “In lower elevation and flatter terrain, you’re not getting that as much.”

“[There’s] good news for your county, as far as drought status, especially compared to the rest of the state,” Merrill said. “This year, you’ll see, has also been a pretty good winter — just some abnormally dry conditions, mainly in the western part of the county.”

Due to a lack of low elevation snow pack this year, Merrill pointed out significant differences between last spring and now.

“If we look back at this time last year ... we had a pretty good spike at the Bear (River) coming through town, kinda had a few good spikes. The first low elevation snowmelt spike, then later in the year the high elevation spike,” he said. “This year, you’re not going to be seeing that similar thing.”

Merrill reported nearby basin area moisture levels, acquired through snow telemetric measuring unit sensor data (SNOTEL), indicate that the Upper Bear basin is sitting at 96% of normal; Blacks Fork at 107%, and further east toward Flaming Gorge reporting roughly 93%.

“It really started turning in February and March — that’s when we started seeing more frequency of storms,” Merrill said, presenting comparative historical SNOTEL data. “We had a pretty good snow drought in January. It wasn’t until we got into February and March that we really saw things starting to take off.” 

While the peak of the La Niña occurred in December, Merrill said there’s often a two-month delayed response.

“Since February, we’ve had more consistent than not in frequency and magnitude of storms. Currently, we’re sitting at 15.9 inches of snow water equivalent (SWE) averaged across the (Upper Bear) basin.”

“A lot of these sites are pretty high elevation in the Uintas,” he continued. “Typically, you don’t start seeing any melt until getting on toward the end of April or May ... it (the snowpack) became more dense earlier than it typically does. When you hit a critical density, that’s when things are isothermal. Any time you warm up, instead of that snow compressing and not melting, you start the melt process ... even at these higher elevations, easily about two weeks early. Upcoming weather will dictate how it comes down the hill.”

Blacks Fork reported 14.4 inches SWE. “It’s ready to shed,” he said.

Lower elevated Flaming Gorge/Upper Green basin area is melting in excess of one inch per day, he reported. “That’s a pretty strong melt rate ... and several weeks early.”

Water volume supply estimates also factor in soil moisture status.

“If soils are dry, you’re going to be losing that melt into the soils first... The more moist the soils, the more efficient the runoff will be.”

The SNOTEL site data indicated normal soil saturation for the Upper Bear basin while Blacks Fork is a bit below normal at 70%. The Flaming Gorge area is currently at 120% of normal.

“They’re so high as a direct result of the snowmelt that’s already occurred earlier than normal,” Merrill said.

Forecasted water supply volume for April-July is 86% of average due to near normal snowpack and soil saturation levels between 70-90%. Peak river flow forecasts a mere fiftieth percentile, or “much lower than a flood flow,” Merrill said. “Mostly driven by higher elevation melt ... we’re well below flood levels throughout all the ranges of possibilities” at the Bear River.

Blacks Fork River water flow volume is about 75% of its average because lower elevations were hit hard with drought conditions last October, causing significant evaporation of soils, despite current moisture levels reported at 107%.

Merrill also outlined nearby reservoir capacity levels. Meeks Cabin, he said, “is quite low right now; certainly no concerns for imminent spilling in the near future.”

Smith’s Fork is generally below average water supply despite “good snowpack because you’re going to be losing it to the soils.”

Stateline Reservoir is currently sitting at 36% capacity versus its typical 48% average.

“[It’s in] better shape capacity wise than Meeks; no imminent potential unless there’s an extreme weather event that would cause spilling,” he said.

“The last couple of years, reservoir operators have had to take flood control measures in advance preemptively to make room in the reservoirs for what was coming down,” Merrill said. “This year, we’re seeing mostly status quo operations as normal.”

“Weather will dictate how everything transitions from here on out throughout the snowmelt runoff season,” Merrill said as he briefed attendees of the weather forecasted through the rest of April, namely persistent high-pressure, warming trends and dry, stable conditions.

“Any subsequent warmup we see is going to start bringing that snowpack off the hills,” he said. “[We’ve had] earlier than normal runoff even for the highest elevations, but at least we’re in good shape and below normal precipitation.”

Merrill announced the end of winter, though reminded emergency personnel of the common risks that occur during seasonal transitions. 

“We’re transitioning out of winter, heading deep into the warmth of spring, moving forward the next few weeks,” he said. “Even though you’re far from a flood flow, spring runoff is always hazardous [because of] high flow conditions, swift water. Very, very cold water temperatures always pose a threat to the public.”

Uinta County could potentially see more progressive storms moving through the latter part of April.

“La Niña years with extremely low snowpack can allow the air mass to warm much quicker, and that warming is what drives monsoonal moisture,” Merrill said.

Expecting a likelihood of above average temperatures and below normal precipitation, he further cautioned that “earlier than normal runoff lengthens the warm season ... and it lengthens the fire season.” 

Uinta County Emergency Manager Josh Rasnake also briefly introduced attendees to a new, still-developing statewide emergency program called “Ready, Set, Go!” 

“Ready will essentially be ‘always be ready all the time,’” at least two weeks early, according to Rasnake. “Set will be ‘there’s an active situation, make sure you have your stuff packed.’ And Go will be ‘you need to leave the area now,’” said Rasnake.

The next LEPC meeting is scheduled for 2 p.m. on July 17 in the EOC room at the Uinta County Complex. 

There is also an upcoming Modular Emergency Response Radiological Transportation Training (MERRTT) training from 8 a.m. to 5 p.m., on May 12-13. The course is offered free of charge to a variety of emergency responders. For more information, contact Rasnake at 307-783-0327, or email at jorasnake@uintacountywy.gov.