Ice jam forms near Manderson; flood warning extended through Monday

After Saturday morning flooding raised concerns in Worland, officials throughout Big Horn County are preparing to mobilize Emergency Management operations in order to mitigate the potential impact of ice jams in communities along the Big Horn River.

According to a statement released by Worland Police Chief Gabe R. Elliott, law enforcement officials began evacuating low-lying areas of Worland after water from the Big Horn River flooded parts of the town. As of Saturday afternoon, the National Weather Service (NWS) office in Riverton reported that the river swelled to a gage height of 14.59 feet, indicating major ice jam flooding on the Big Horn River in Worland.

Citing the unpredictable nature of river ice and ice jams, the National Weather Service (NWS) office in Riverton extended their flood warning for communities along the river to Sunday afternoon. Chuck Barker, a lead meteorologist at the NWS in Riverton, attributes this incident to the gradual shift toward warmer temperatures.

“After being there for several months, the ice in the river gets anywhere from 10 to 20 inches thick. As it warms up, [the ice] starts to break apart and backs up, [blocking] the channel,” he said.

Barker said we could anticipate a prolonged flood and response cycle, adding that various stages of thawing and melting will occur over the next month. While we’ll experience a slight warm up in the coming week, according to him, the region will witness near-normal temperatures through March.

“We’re not going to see [temperatures in] the upper 50s or 60s which would really accelerate river melt,” he said. “The biggest thing we’re going to want to see is at least a three- to four-day period of exceptionally warm temperatures. Right now we’re looking at a moderate warm up, but nothing like what we’ve seen.”

For county officials, Worland’s flood problems brought back memories of the 2014 ice jam. Three years ago, an ice jam on along the Big Horn River caused major damage to six residential properties in Big Horn County, minor damage to 14 more residential properties and major damage to at least two businesses. The state declared a state of emergency, authorizing the Wyoming Office of Homeland Security and Wyoming National Guard to assist in proactive and reactive relief efforts.

A 2014 ice jam at the Big Horn River in Greybull threatened to flood parts of the town. The town's levee can be seen running along the top of the photograph. Photo by Lisa Kunkel
In 2014, an ice jam on the Big Horn River threatened to flood parts of the County. In Greybull, residents feared the jam would cause flooding to residences and businesses throughout town. Along the top of the photograph the river’s crest can be seen nearly at the top of the levee.
Photo by Lisa Kunkel

On Friday, Feb. 10, Governor Matt Mead declared a state of emergency for areas experiencing severe winter storm conditions including but not limited to power outages, rapid snow melt and areal flooding. The declaration authorizes the Wyoming Office of Homeland Security and Wyoming National Guard “take all appropriate and necessary actions… in response to and in advance of [the] actual disaster.” National Guard units are currently assisting operations in Worland, and may move north to Manderson, Basin and Greybull should the need arise.

According to Big Horn County Sheriff Ken Blackburn, the County’s response began around 3:30 a.m. Saturday with operations in Manderson. While Blackburn said the situation looked promising that afternoon, he cautioned that the situation could change quickly given the proper circumstances.

“You can never tell with Mother Nature, but it’s got all the earmarks it had in 2014. I’ve seen way too much to say it won’t go over the levee, and way too much to underestimate the force of nature.”

Blackburn said that the county is working in tandem with officials from Greybull Public Works and officers from the Greybull Police Department to monitor river’s water level. In Manderson, emergency response crews are sandbagging areas of the levee that need additional support to mitigate the potential impact of a flood.

According to Rodney Ross, Greybull’s emergency management lead, the town began preliminary preparations but has yet to fully mobilize their operation.

“It’s not panic time yet,” he said, adding that there are other things the town will do prior to sandbagging and ordering evacuations. “When it gets to a certain level, we’ll close the floodgates on the levee to prevent water from flowing into town.

While Ross said it was too early to tell which direction the incident will go, he suggested those who wish to err on the should prepare sandbags for lower floors and windows, and devise a worst-case-scenario evacuation plan in the event of a mandatory evacuation order.

“I don’t want people to respond like ‘Chicken Little’ to the sky falling,” Blackburn said, echoing Ross’ sentiment against overreaction. Although he cautioned against panic and overreaction, Blackburn conceded that those with “items of great value, vehicles or livestock” along the floodplain should consider preparing for a potential flood.

Blackburn said the next few weeks will be a challenge, adding that the situation has “very high potential” to change. Despite the uncertainty, he remains confident that the area will remain strong in the face of potential damage.

“The communities are very resilient,” he said. “[Flooding] is just part of the great life we live and location we’re in — we’ll adapt to whatever mother nature throws at us.”

UPDATE (Feb. 12, 4:00 p.m.): The NWS has extended their flood advisory to Monday, Feb. 13, at 4:15 p.m as Big Horn County begins to experience minor flooding in low-lying areas. In anticipation of rising waters, volunteers and emergency management personnel have prepared and deployed an estimated 2,000 sandbags along the Big Horn River in Manderson.

According to Sheriff Ken Blackburn, an ice jam has formed near Manderson prompting community leaders to prepare a disaster declaration. The declaration by Manderson will allow the town to formally receive state assistance.

Blackburn said the state is beginning to mobilize their response; according to him, an advance team will make their way to the area tonight with more assistance expected tomorrow.

 

Emergency management personnel will be briefed on the situation tomorrow at 7:30 a.m. in Worland. Later that day, sandbagging efforts will begin in Greybull at 1:00 p.m near the baseball field.

As the situation continues to develop, Blackburn remains cautious of the circumstances.

“[It’s] got all the earmarks of another bad year,” he said, “but we just don’t know yet.”