The Yampa River is about two weeks ahead of historical summer low-flow time, but officials say the fish population is not being stressed too badly by the early conditions.
Experts say the snow melt started early, which caused peak river flows to be about two weeks early.
Now, data show the Yampa River's low flow has arrived about two weeks early, too.
The river appeared to reach its lowest flow July 9, dropping down to a water flow reading through Steamboat Springs of 115 cubic feet per second, according to the U.S Geological Survey.
Midsummer the flow usually averages 117 CFS, according to 91 years of historical USGS data of the Yampa River through Steamboat.
The river is back on the rise, however, running around 170 CFS on Saturday. The 91-year mean for that date is 255 CFS.
Colorado Division of Wildlife biologist Kevin Rogers said the danger of low water is that it affects fish habitat.
"The water can warm up faster," he said.
Native trout to the Yampa River are considered cold-water fish, thriving in water that is between 50 and 60 degrees. When the river flow goes down, water can rise above 70 degrees, which puts stress on the fish, Rogers said.
Rogers measured the temperature of the river at 61 degrees on Friday.
"So we are still in pretty good shape," he said.
Angler Jeff Ruff, from the Steamboat Fishing Co., said the biggest evidence of the river getting warmer is in the fish's eating habits. They only feed during cool periods of the day, usually in the morning and the evening which he has been seeing in July on the Yampa River.
Low water also can decrease the amount of oxygen in the water, he said.
A combination between warm water and low oxygen can ultimately mean trout will begin dying in the river.
"We haven't had any reports on fish kills (on the Yampa). We seem to be alright, so far," Rogers said.
However, fish kills due to low water did occur on the Williams Fork River earlier in the summer, he said.(Doug Crowl is a reporter for the Steamboat Springs Pilot/Today.)