Record rains bring flooding to Fremont CountyWritten by Natasha Wheeler
Fremont County – Flooding in Fremont County last week was due to record rainfall in the area, and more flooding is possible this spring.
The two-day rainfall in Lander on May 6-7 was the third wettest consecutive two-day period on record. The second wettest was recorded in May of 1924, and the most precipitation in Lander over a two-day period occurred in April of 1895.
“Lander also set the daily record for rainfall on May 7,” adds Charles Baker, National Weather Service meteorologist in Riverton.
The area above Fort Washakie on the North Fork of the Little Wind River received 6.88 inches of precipitation over two days, and although there are no long-term records for that area, it is likely a record volume.
“This event was interesting in the fact that it significantly flooded the Little Popo Agie and its tributary Twin Creek. The Middle Fork of the Popo Agie that goes through Sinks Canyon and Lander, while it rose, did not do any significant flooding in the city of Lander,” Baker explains.
The majority of flooding in the Lander area occurred on the northwest side of town where the North Fork of the Popo Agie, Baldwin and Squaw Creek waters merge.
“We had flooding on the Little Wind River and on the Little Popo Agie going through Hudson. Also, the Middle Fork of the Popo Agie and the Little Popo Agie meet on the northwest side of Hudson and flow into the Little Wind, so that also helped increase the flooding at Arapaho, through southern Riverton,” he continues.
The Big Wind River coming out of Togwotee Pass, through Dubois and Crowheart didn’t experience flooding on May 7-8, however the soils in those drainages have become saturated and could be potential flood zones if precipitation continues in the coming weeks.
“We haven’t even seen the high point of our flooding. This flood was almost all rain-caused, and we haven’t even hit the snowmelt runoff yet,” comments Alex Malcolm of University of Wyoming Extension in Fremont County.
The snowline for last week’s storm was at about 8,000 feet of elevation, and snowpack increased over the two days of precipitation.
“On the east slope of the Wind River Range, the snowpack is similar to this time of year in 2010 when we had significant flooding due to snowmelt,” remarks Baker, adding that snowpack in the Wind River Basin is currently at about 140 to 150 percent of normal for this time of year.
Snowmelt runoff usually occurs through the first half of June, and additional precipitation is forecast before that time this year.
“If people had flooding in 2010 or flooding in the Wind River Basin over the last decade, they should look and see what’s changed. Have conditions improved? If they are the same, people should take action,” he comments.
Planning for more water
Building large structures or levees to barricade waters is not likely possible in time for this spring’s runoff, but residents in low-lying areas should take what precautions they can to mitigate potential damage.
“If we know we’re in a low-lying area, we should move our livestock to a higher area and locate some of those areas, such a neighbor’s place that is out of the floodplain,” Malcolm suggests.
Baker also reminds producers that equipment can be heavily damaged if it is submerged in water and recommends moving it out of potential flood zones.
“When our farm equipment is parked all winter, it doesn’t really matter where it is, but we should move our tractors, trucks and cultivating equipment to the highest places we can park them,” he says.
Issues related to standing water may also pose a challenge this season, and Malcolm comments there could potentially be in increase in mosquitos, diseases and funguses related to recent damp conditions.
“There’s no way for the water to dissipate, other than through evaporation, which will cause more concern with salinity in those low-lying areas, especially in Fremont County. We might have to do some remedial work in terms of reseeding or growing those crops,” he says.
Other areas in Wyoming saw flooding last week, as well, though precipitation levels are variable throughout the state.
“On the Laramie River, there has been flooding, and the North Platte above Seminoe Reservoir is very high. There are also areas of concern through the Saratoga, Encampment and Riverside area, and there is high water and potential flooding on the Little Snake River in Baggs,” Baker remarks.
The Upper Green River Basin and areas above Fontenelle Reservoir have seen significant precipitation, as well, along with areas along the Big Sandy River.
However, looking at snowpack levels, Baker also states, “A lot of the western part of the state is below normal and significantly below normal in Yellowstone and Teton County. Conditions in the Big Horns are slightly below normal.”
In Fremont County, the Extension office has been working with the fairgrounds and emergency management services to secure facilities for livestock and residents affected by flooding.
Malcolm reminds residents, “We have resources at our Extension offices to help with ideas for remediation, where to go for emergency disasters and how to work with other federal agencies. We have a lot of resources available.”