May 16, 2012
Save Email Print Bookmark and Share
A A
Reporter: National Weather Service - Hastings Email

SIGNIFICANT SNOWMELT THROUGH FRIDAY MAY CAUSE FLOODING


A SOLID SNOWPACK OF 2 TO 8 INCHES REMAINS IN PLACE ACROSS MUCH OF SOUTH CENTRAL NEBRASKA. IF YOU MELTED THIS SNOW DOWN...THE LIQUID EQUIVALENT RANGES FROM AROUND 1 INCH TO 1.5 INCHES.

HIGH TEMPERATURES TODAY WILL CLIMB INTO THE 40S AND SOME AREAS MAY EVEN REACH INTO THE LOWER 50S BY FRIDAY.

THESE TEMPERATURES WILL RESULT IN RAPID SNOWMELT.

FROST DEPTH MEASUREMENTS SHOW THAT THE GROUND IS FROZEN SOLID FROM THE SURFACE TO A DEPTH OF 15 TO 25 INCHES. CONSEQUENTLY, SNOWMELT RUNOFF WILL BE EXTENSIVE AS THE GROUND WILL NOT HAVE TIME TO THAW
AND WILL BE UNABLE TO QUICKLY ABSORB MUCH OF THE MOISTURE.

RIVER GAUGE SITES ALONG THE PLATTE...NORTH LOUP...AND LOUP RIVERS SHOW THAT IN SOME AREAS THESE RIVERS ARE ALREADY RUNNING VERY HIGH AND JUST BELOW FLOOD STAGE. CONSEQUENTLY, ANY ADDITIONAL RUNOFF MAY QUICKLY PUSH THESE RIVERS INTO FLOOD.

ICE JAMS HAVE ALREADY CAUSED NUMEROUS PROBLEMS ALONG THE PLATTE RIVER AND MANY OF THESE JAMS HAVE YET TO FULLY BREAK UP. THEREFORE, ADDITIONAL RUNOFF COULD RENEW ICE JAM FLOODING ALONG PORTIONS OF THE PLATTE RIVER.

ALTHOUGH THERE HAVE BEEN NO SERIOUS ICE JAMS YET THIS
SEASON WITHIN THE LOUP RIVER BASIN, THIS BASIN IS AN ICE JAM PRONE AREA. THEREFORE, WHEN THE ICE BEGINS TO BREAK UP THE NEXT SEVERAL DAYS, ICE JAM FLOODING MAY ALSO OCCUR WITHIN THE LOUP RIVER
BASIN.

ALTHOUGH THE ICE WILL BEGIN TO BREAK UP THE NEXT FEW DAYS WITHIN THE PLATTE AND LOUP RIVER BASINS, THE WARM UP WILL BE SHORT LIVED AND SUBSTANTIAL ICE MAY POTENTIALLY REMAIN IN THESE RIVER SYSTEMS THROUGH MUCH OF FEBRUARY. THE THREAT OF OCCASIONAL
ICE JAM FLOODING WILL ALSO PERSIST IN THESE AREAS UNTIL MOST OF THE ICE CAN MELT AWAY.

THE GREATEST THREAT FOR SNOWMELT RUNOFF FLOODING WILL BE WITHIN THE PLATTE AND LOUP RIVER BASINS. HOWEVER, OTHER BASINS SUCH AS THE LITTLE BLUE AND WEST FORK OF THE BIG BLUE WILL ALSO BE AT LEAST
SLIGHTLY SUSCEPTIBLE TO SNOW MELT FLOODING.

FURTHER SOUTH, THERE IS LITTLE TO NO SNOW REMAINING ACROSS THE REPUBLICAN AND SOLOMON RIVER BASINS OF EXTREME SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KANSAS. SNOW MELT FLOODING IS NOT EXPECTED OVER THESE AREAS.


powered by Disqus