Some Greeley residents have been told to evacuate because of high water along the Poudre River.
A combination of warm weather and more afternoon thunderstorms will keep snowpack melting and water levels on the rise.
Some storms later this week could produce locally heavy rain that may add to the flood concerns.
The National Weather Service is warning of minor flooding after advisories were issued for rivers in northern and central Colorado.
The record snowpack in the Rocky Mountains in Colorado has also been creating record river flows as the snow begins to melt in the rising June temperatures.
Monday was the hottest day of the year in the state, prompting flood advisories and warnings for parts of northern and western Colorado, officials said.
The flooding in the high country has started and high water will be with around for awhile.
State water managers say flooding in Denver from the state’s record snowmelt is unlikely.
Homeowners are working now to prevent problems later along the Poudre and Big Thompson rivers.