874  
FGUS75 KBYZ 072039  
ESFBYZ  
MTC003-009-037-067-095-097-107-111-WYC033-092100-  
 
HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE BILLINGS MT  
239 PM MDT WED MAY 7 2025  
 
...WARM TEMPERATURES TO BRING INCREASED FLOWS ON RIVERS AND STREAMS  
BY THIS WEEKEND...  
 
WARM TEMPERATURES ARE FORECAST THROUGH EARLY NEXT WEEK. THIS IS  
EXPECTED TO INCREASE SNOWMELT ACROSS AREA MOUNTAINS, RESULTING IN  
A SIGNIFICANT INCREASE IN FLOWS ON AREA RIVERS AND STREAMS BY THIS  
WEEKEND. WHILE FLOODING IS NOT ANTICIPATED ON LARGER RIVERS AND  
STREAMS, THERE IS A CHANCE THAT SOME SMALLER STREAMS AND CREEKS  
COULD REACH BANKFULL IN AND NEAR THE FOOTHILLS, PRODUCING MINOR  
FLOODING. AT THE VERY LEAST STREAM FLOWS WILL BE MUCH HIGHER WITH  
THE INCREASED SNOWMELT.  
 
WATER RISES WILL OCCUR FIRST ON SMALL STREAMS AND CREEKS FLOWING OUT  
OF THE FOOTHILLS, EVENTUALLY ARRIVING ON LARGER RIVERS AND STREAMS.  
THE RATE AND STRENGTH OF THE WATER RISES WILL BE DETERMINED BY HOW  
WARM TEMPERATURES GET OVER THE MOUNTAINS, AS WELL AS WHETHER  
TEMPERATURES REMAIN ABOVE FREEZING OVERNIGHT. ANY PRECIPITATION WILL  
ALSO RESULT IN STRONG AND SUDDEN WATER RISES.  
 
FOR THOSE LIVING NEAR WATERWAYS, THIS MAY BE THE LAST CHANCE TO  
FINALIZE PREPARATIONS FOR RUNOFF SEASON. MOVE ANY LIVESTOCK AND  
EQUIPMENT TO HIGHER GROUND AWAY FROM WATERWAYS. ANY STREAM BANK  
STABILIZATION ACTIVITIES SHOULD BE COMPLETED AS SOON AS POSSIBLE.  
FOR THOSE PLANNING RECREATION ACTIVITIES ON OR NEAR WATERWAYS, BE  
PREPARED FOR CHANGING CONDITIONS AND SIGNIFICANTLY HIGHER FLOWS.  
 
EROSION WILL ALSO INCREASE AS STREAM FLOWS INCREASE, MAKING  
STREAMBANKS UNSTABLE. PLEASE STAY WELL AWAY FROM STREAMBANKS WHEN  
WATER IS RUNNING FAST, AND BE ESPECIALLY VIGILANT WITH CHILDREN.  
EROSION WILL UNDERCUT THE BANK AND CAN BREAK OFF TAKING THE BANK  
AND ANYONE STANDING ON IT INTO A VERY COLD RAGING CURRENT.  
 
STAY TUNED TO THE FORECAST FOR ANY WATCHES, ADVISORIES, OR WARNINGS.  
PLEASE REPORT ANY FLOODING TO LOCAL LAW ENFORCEMENT AND HAVE THEM  
RELAY THE REPORT TO THE NATIONAL WEATHER SERVICE.  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab MT Page
The Nexlab WY Page Main Text Page