Ice jams on Big Horn cause extensive flooding
by nathan oster
It was the day when everyone, it seemed, went to see the river.
Sunday, March 9, 2014 won’t soon be forgotten — a day of shock, anxiety, concern … and ultimately, relief from Mother Nature herself in a crisis triggered by ice jams on the Big Horn River.
By late Tuesday night, it was nearly over. A release issued earlier in the day from the emergency management center at Greybull Town Hall indicated that the last remaining ice jam on the Big Horn River south of Manderson had broken up overnight. Ice was packed up near the Big Horn River bridge in Manderson, but was water flowing freely beneath it.
In Greybull, the river was flowing freely, the only ice in sight lying in chunk form between the river itself and the levee that protected the town from its closest call in a half century, since the levee was built in the 1950s at the urging of then Mayor Oscar Shoemaker.
According to preliminary county estimates, the ice jams 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.
Several of them are in the Greybull area, including homes owned by Joe and K.C. Yarborough, LaVon Castro and Leona Foulk. Flooding was also reported north of town, damaging tracks that M-I Swaco relies on to move product as well as at the McFadden Ranch.
Through multiple interviews, a timeline of events emerges.
National Guard units had been in the Worland area, dealing with flooding and ice jams on the Big Horn River on Friday. In time, those jams broke up. No explosives were ever used to accomplish that, according to several of the emergency management personnel who followed the ice jams to Greybull later in the weekend.
The town was in the information loop on Saturday — but the first sign of trouble didn’t emerge until around 1 a.m. Sunday, when Town Foreman Dalen Davis received notification that there was flooding at the sewer lagoon north of town.
Now long after he notified Mayor Bob Graham, who went out to take a look for himself.
Eventually the lagoon lost its electrical power.
“We knew the power panel had been compromised,” said Graham.
Rocky Mountain Power was dispatched to the scene.
Graham informed the Department of Environmental Quality, which authorized the town to begin pumping sewage over the levee and into the Big Horn River as a way of keeping the water from backing up into the basements of homes around town.
At 6 a.m., a state of emergency was declared in Greybull, a step that Graham said was needed to access emergency funding. Sometime around then, Big Horn County followed suit with an emergency declaration of its own.
The initial flood control efforts were focused on homes on the north end of town.
The Wyoming National Guard sent troops to assist in the sandbagging efforts.
Later in the day, the group was split, with some staying to help homeowners on the north end of town and the rest shifting their focus to the lowest part of the town’s levee, which is between Sixth Avenue North and Eighth Avenue north.
While this was going on, all eyes were on the rising river. Ice jams were reported all along the stretch between the oxbow on the south end of town and the MI-Swaco bridge a few miles to the north.
On three occasions, the longest lasting 10 to 15 minutes, the Greybull Police Department closed the Big Horn River bridge, preventing motorists from crossing. It did so on the orders of the Wyoming Department of Transporation, which was concerned with not only the level of the river but also the size of the chunks passing under the bridge.
Brenner said the first shut-down occurred around noon. Another one was at 3. The third and final one happened when the jam broke and the ice started moving quickly along the river.
“I know we upset some people by doing that, but I wouldn’t have wanted to drive across that bridge,” said Brenner. “You could feel the ice chunks slamming into it. They would rock the bridge. It was spooky, actually. Some of those ice chunks were the size of semis. Luckily the bridge held up.”
Throughout the day, local residents trekked by the hundreds to the levee and the bluffs to the east to monitor the river. At one point, with large crowds milling along the levee, the police were asked to move them.
Greybull Fire Chief Paul Murdoch’s day began with a phone call he received around 5 a.m. on Sunday morning. He and Chuck Spragg were pressed into duty, first at the sewer lagoon, where they were tasked with getting the pump started that would direct sewage into the river.
The full fire department was called out around 7:30 or 8 that morning, and their initial focus was on sandbagging, which they did on the residential properties on the north end of town, as well as at the city shop.
Murdoch said he spent the day “bouncing around from place to place.”
He didn’t get worried until around 3 p.m., when the river surged to within inches of going over the levee, mostly between Sixth Avenue North and Eighth Avenue North, where it is at its lowest point.
“When we got that little surge around 3, I thought we were in trouble,” he said. “I had heard another surge would be coming.”
Graham said he, too, was concerned, but all along, “I had faith in the levy system. It had held everything out since the 1950s, and it had seen high water before. But I will say that (at its worst point Sunday afternoon) the water level was the highest its ever been, at least in my 27 years in this community. I was definitely concerned.”
Throughout the afternoon, town officials and the various agencies involved — Department of Homeland Security, the U.S. Army Corps of Engineers, the Wyoming National Guard, the Big Horn County Sheriff’s Office and Big Horn Search and Rescue, among others — focused on two primary issues.
The first was, what could be done to break up the ice jam.
Graham said explosives were considered at the command post at Town Hall, but that “the comments from the Corps and Homeland Security people were that explosives had been tried time and time again on other ice jams, without success. They said unless they’re properly placed, they rarely do any good. Unless you can get them under the ice and blow it into the air, it’s basically a feel-good exercise only.”
Both Graham and Murdoch said they were going to investigate “whatever means they could” to spare the town. Murdoch contacted a demolitions expert in Powell, but he didn’t have the required explosives on hand. The earliest he could have had them here was Monday morning.
“He wouldn’t have been able to help us,” Murdoch said.
Graham said there was also talk of getting a trackhoe and trying to break up the jam from the MI-Swaco bridge. “We couldn’t find one anywhere close to here with a long enough reach,” Graham said.
“Those were really our only two options at that point, other than hoping that Mother Nature would take its course.”
That led to a second issue: What could be done if water starts pouring over the levee.
“At that point, we felt that with the sidewalk on top of the levee, it wasn’t going to split the levee. So what we were preparing to do was to direct the water wherever it came over the levee to the storm drains or lift stations, where we could get some pumps in so that we could pump it back into the river,” said Graham. “I know it sounds silly. Water’s coming over the levee and you’re going to pump it back over the levee into the river. But you have to try something to keep it from flooding the town. You can’t just let it happen.”
The other major precaution that was taken Sunday was to fortify the low spots on the levee, mainly between Sixth and Eighth Avenues. Initially sand bags were used. In time, WYDOT brought jersey barriers. Using equipment from Larry Anderson, Bill Hunt and Clay Collingwood and the manpower of firefighters and volunteers, the barriers were placed atop the levee. This work continued throughout the evening, until around 9:30 p.m. with approximately 50 going down.
By then, things were considerably less tense. The ice jam started breaking up shortly after 6 p.m. Those who witnessed it reported seeing a momentary surge, followed by a rapid retreat of water.
At around 6:15 p.m., Graham received a call from Joe Cheatham, who was at the MI-Swaco bridge. Cheatham reported that the ice jam had broken up, and that water was starting to move freely again, pushing ice chunks to the north.
Graham said he and Murdoch were riding in a truck when they got the news.
“There were some high fives,” said Graham.
Murdoch added, “Mother Nature is what saved our butts.”
“I was worried about the dike coming apart,” said Murdoch. “We can tell (FEMA) now that we’ve certified the dike. It works.”
Commission Chairman Jerry Ewen said the community made an impression on him. “One thing I saw in Greybull was the community spirit,” he said. “Everyone got together with a common purpose. Nobody was asking, ‘Am I going to get paid?’ or ‘How much am I going to get paid?’ High school kids came down to help fill sandbags. Everybody had this attitude that they weren’t going to wait for the government to help us. We’re going to work at it ourselves to get it fixed.”
Jonathan Dyer, a captain in the Wyoming National Guard, agreed.
“Last night around 5, we were sitting here and we were all pretty worried,” he said. “We just had to wait and see what was going to happen. Finally at 6 our engineer came from the bridge and said he’d heard a big crack, and that the water started to flow. There was a huge sigh of relief everywhere.
“Between 5 and 6:30, it was just like the entire town decided to get together and start to work on this. All the effort they put in … the way they put themselves on the line yesterday to save their town. That was the takeaway for me. It wasn’t any type of national or state response that saved the day. It was the community, showing what it’s made of.”
Added Graham, “It’s been one big team effort. It seems to have all worked out well. Everybody did their job. The levee did too.”
As a result of all the planning that occurred, the town and for that matter the whole surrounding area will be better prepared for high water due to mountain runoff. Thousands of sandbags were filled and will be stored around the community.