Ice break advisory remains all week along section of Roaring Fork River

With the current weather conditions expected to last into the weekend, those fishing or recreating on a midvalley stretch of the Roaring Fork River this week need to be careful of more ice breaks and high water, officials are warning.

There have been at least two ice jam releases in the past month, and the National Weather Service office in Grand Junction has issued a “hydrologic advisory” through 3:15 p.m. Sunday for the section of the river from Snowmass Canyon to Carbondale.

Kris Sanders, a meteorologist at the Grand Junction office, said Wednesday the weather pattern of cold nights and fast warming during the day in the forecast increases the potential for ice build up and potential releases.

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“Usually you have a period of cold temperatures, way below normal, which is what we had … near zero or below, and that helps freeze the river,” Sanders said. “Then when you have sudden increases in temperatures, which is expected this week, then any jams within the river can release.”

With stream flows below average coupled with the very cold temperatures, anchor ice, which is submerged ice attached or anchored to the riverbed, and bank ice formation is high, Roaring Fork Conservancy officials said in last week’s report for the Roaring Fork watershed. At the peak heating of the day the ice can release and cause backups downstream, and the ice dams eventually break.

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That has been recorded twice this winter near Snowmass Canyon — on Christmas Day and again Tuesday. Sanders said ice jams are not uncommon for this time of year, but often happen closer to spring.

The National Weather Service forecast for the rest of this week in the Old Snowmass area calls for lows ranging from 5 degrees to 13 degrees at night and warming to the mid-30s in the afternoon. The advisory is for the section from Snowmass Canyon to Carbondale.

Those fishing sections of open water should stay on the banks or be ready to react and watch for high water during the day, they warn. The two releases recorded this winter came at 2 p.m. in December and 4 p.m. this week.

The Roaring Fork Conservancy, a Basalt-based nonprofit, has posted videos to its Facebook page of the recent ice breaks, watching from Lower Roaring Road near Old Snowmass and the confluence of Snowmass Creek into the Roaring Fork River. The recent video, shared by Megan Rash and Jen Klink, was taken about 4:10 p.m. Tuesday.

In the post, the nonprofit said about a mile downstream from Lower River Road bridge some of their staff was at the Lazy Glen Open Space and observed ”a very large ice field/blockage — essentially the slabs of ice moving downstream from this release get stuck/sieved in this section. While further downstream maybe won’t see the same huge ice slabs downstream of this ice field, where is a significant wave of water that will make its way downstream.”

After the Dec. 25 ice break (recorded by Pitkin County Sheriff’s Deputy Anthony Todaro), the riverflow at Emma went from 138 cubic feet per second (cfs) to 522 cfs and flooding was seen four miles downriver at what is know as the 7-Eleven bridge in Basalt.

Sanders said the conservancy acts as the “eyes and ears on the ground” to scout the river for the weather service, and the NWS uses their input for the forecasting. He added just because there was a major break Tuesday that doesn’t mean the river is clear.

“They called yesterday (before the ice break) and said they were concerned, so we put out the advisory for the entire warm period,” Sanders said Wednesday. “Even with Tuesday’s break up, people recreating on the river should still be at a high awareness. It can build up again with the expected cold at night.”