ESFBYZ The latest snow data from the NRCS and NOHRSC shows a significant snowpack existing between 5500 and 7500 feet. In this elevation 3 to 7 inches of water is contained within the snowpack. A storm system is expected to impact the area from Sunday afternoon through Monday. From Sunday afternoon into early Monday morning temperatures will be warm enough for rain to fall in this mid elevation layer over the Beartooth, Absaroka and Crazy mountains and foothills. The Pryor and Bighorn mountains and foothills will see rain potential from late Sunday evening into early afternoon Monday. A few thunderstorms may bring locally heavy rainfall Sunday afternoon into Sunday evening. Snowmelt models are estimating half of this mid elevation snowpack could melt out during the rainfall period. With 1 to 2 inches of rain in the forecast, this means an additional 1.5 to 3.5 inches of water contribution from snowmelt. Total water event could be 2.5 to 5.5 inches if these forecasts are correct. Anywhere snowpack is present, the ground underneath is likely frozen resulting in quick runoff until reaching unfrozen ground at lower elevations. Burn scar areas will also see rapid runoff due to burnt soil conditions, including the Robertson Draw, American Fork, and Elk burn areas. Smaller creeks and streams will see the highest potential for flooding with this event. Forecasts for the larger rivers in our area show up to 3 times the current flows by Tuesday, though water levels remain well below flood stage. Water may flow overland and across roadways creating difficult to dangerous foothills travel. Low lying areas may fill with water creating additional property flooding. The severity of the impacts will depend on how quickly and how much the snowpack melts, in addition to the amount of rain that falls on top of the snowpack. While flooding is not imminent, now is the time to move equipment and livestock out of low lying areas, and away from waterways. If you are downstream from a burn scar, have an evacuation plan ready should conditions become dangerous. Do not drive over flooded roadways as the roadbed may be washed out. Be especially careful driving at night when water covered roadways are less visible. This period is not a good time to recreate in the foothills, but anyone that is recreating in these areas should expect changing conditions and use extreme caution near waterways. Do not camp in low lying areas adjacent to streams. There is still uncertainty with this storm system. Stay tuned to the forecast through the weekend for the latest trends, along with any watches, warnings or advisories that may be issued. Please report any flooding to local law enforcement and have them relay the report to the National Weather Service.
