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Flood watch: 'It's all coming together'

Jun 2, 2017 By Katie Roenigk, Staff Writer

Conditions have combined to create flood concerns for the next few weeks in the Wind River Basin.

"It's all coming together," National Weather Service meteorologist Chuck Baker said Friday. "We've reached that period where after Memorial Day it magically turns into summer. (The snow) is going to come off."

His agency posted several warnings Friday, including information about a flood watch that is expected to last through the end of next week.

Baker said flooding hazards could be present even longer than that, however, due to the level of snowpack remaining in the mountains.

For example, Togwotee Pass, at 9,580 feet, still had 62 inches of snow at the end of the day Thursday - an equivalent of 27 inches of water.

On South Pass, at 9,040 feet, there was 47 inches of snow Thursday, equating to about 22 inches of water.

"That's a massive amount of snow," Baker said. "(South Pass) should be at 0 now."

He also pointed to Hobbs Park, at 10,100 feet, with 62 inches of snow equating to 27.5 inches of water Thursday evening, and Deer Park, at 9,700 feet, which showed 56 inches of snow equating to about 28 inches of water.

"There's no way (these sites) are going to get down to 0 without flooding," Baker said. "This is probably a one in at least 100-year event. ... It's considerable."

Multiple factors

In recent history, Baker said, flooding has occurred in the Wind River Basin when snow-water equivalents have decreased by 2 inches a day - typically the maximum possible - over the course of several days. With such high SWEs in the mountains, that means Fremont County could see flooding for at least a week and a half if conditions unfold as forecast.

Daytime temperatures are expected to rise toward 90 degrees over the weekend in the lower elevations, Baker said, translating to the 60s and 70s in the high mountains.

He noted that the warm-up will allow most areas in the mountains to stay above freezing at night.

Temperatures may cool on Tuesday, Baker said, but they will warm back up to the same temperatures by the end of the week.

"And it's going to get windy," he added, explaining that high winds cause additional warming and accelerate snowmelt.

Further, Baker said, the summer solstice is approaching, meaning the days are longer and the sun is at its highest angle, allowing sunlight to hit areas of snowpack that previously were hidden by shade.

Rivers

Waters already had begun to rise in Fremont County on Friday morning, when the Wind River at Riverton was observed just above flood stage (9 feet). It is forecast to rise above moderate flood stage (11 feet) sometime next week.

Also near Riverton, the Little Wind River was measured at a little more than 7 feet Friday morning, still well below its 8-foot flood stage. The waterway is expected to hit 8.2 feet by Tuesday, however.

West of town below Diversion Dam at the U.S. Highway 26 bridge the Wind River already was in moderate flood stage Friday morning and approaching its major stage of 6.5 feet. Closer to Crowheart it was at 9.29 feet Friday morning and was forecast to exceed its 10-foot flood stage by Tuesday.

The Wind River near Dubois was at minor flood stage (5 feet) Friday morning and should stay at that level through Monday. Near Kinnear the river hadn't hit flood stage (9 feet) yet Friday but models showed it would rise to 9.4 feet by Tuesday.

On the other side of the county, water levels were below flood stage Friday morning. Near Fort Washakie the North Fork of the Little Wind River hit 5 feet; flood stage is 6 feet.

The Little Wind River at Fort Washakie was observed at 3.66 feet; flood stage is 4.5 feet. And the North Fork of the Popo Agie River at Gallinger Ranch was observed at 4.59 feet; flood stage is 5 feet.

Emergency management

Officials recommended residents in low-lying areas of the county ensure their properties are shored up for flooding this weekend.

Last month local emergency service agencies said they will not assist with private mitigation efforts and will only respond to life safety incidents that threaten the community.Sandbags are available, however.

Residents are responsible for filling the bags with their own sand or fill material, though Fremont County commissioners last month were planning to make some sand available in Riverton, Lander and Hudson.

Anyone who wants sandbags to fortify their property can pick them up during normal business hours - typically 7 a.m. to 3:30 p.m. Mondays through Fridays - at the Fremont County Road and Bridge shops at 4421 Skyline Ave. Riverton, 856-8122, and 1580 U.S. Hwy. 287 in Lander, 332-2984.

Fremont County began the spring with 80,000 sandbags available. Distribution is limited to 1,000 - preferably 500 at a time - to prevent people from stockpiling materials.

In addition, residents who use Union Wireless can download a Commercial Mobile Alert Service application to receive emergency notifications through an integrated public alert and warning system, and Fremont County has published an evacuation plan on its website to let residents know what to expect if they are asked to leave their homes.

Evacuees should try to stay with friends, relatives, or in local motels if possible, as an evacuation shelter will only be established if necessary.

A representative from the American Red Cross said last month that the agency is unlikely to open a shelter unless all hotel rooms are unavailable.

For further information, contact the Fremont County Emergency Management Agency at 856-2374.

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Water roiled Friday morning through Diversion Dam west of Riverton. Minor flooding has begun upstream from Riverton and is expected to spread in the days ahead. Photo by Dan Bendtsen

Water roiled Friday morning through Diversion Dam west of Riverton. Minor flooding has begun upstream from Riverton and is expected to spread in the days ahead. Photo by Dan Bendtsen


Water roiled Friday morning through Diversion Dam west of Riverton. Minor flooding has begun upstream from Riverton and is expected to spread in the days ahead. Photo by Dan Bendtsen

Water roiled Friday morning through Diversion Dam west of Riverton. Minor flooding has begun upstream from Riverton and is expected to spread in the days ahead. Photo by Dan Bendtsen

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