Ice accumulation reports: December 21, 2009
5 measured ice accumulations were reported to the National Weather Service from freezing rain in the 24 hours ending 11 a.m. EST on December 21, 2009, in 1 state (MT). The largest was 0.25 inches of ice at Geyser, MT. 2 reports were a quarter inch or more, the usual ice storm warning amount, when tree limbs and power lines start to break.
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Ice reports
| Ice | Where | County | Time | Reported to | Source | Remarks |
|---|---|---|---|---|---|---|
| 0.25″ | Geyser, MT | Judith Basin | Dec 21, 12:00 a.m. MST | NWS TFX | Law enforcement | CHOUTEAU COUNTY SHERRIF REPORTS ABOUT ONE QUARTER OF AN INCH ICE ACCUMULATION DUE TO FREEZING RAIN AT GEYSER AND HIGHWOOD. LESSER AMOUNTS REPORTED AT FORT BENTON. |
| 0.25″ | Lewistown, MT | Fergus | Dec 21, 12:00 a.m. MST | NWS TFX | Law enforcement | FERGUS COUNTY SHERRIF REPORTS ABOUT ONE QUARTER OF AN INCH ICE ACCULATION DUE TO FREEZING RAIN. NUMEROUS SLIDE OFFS AND STRANDED BIG RIGS REPORTED BETWEEN LEWISTOWN AND GRASS RANGE. |
| 0.10″ | 2 SW Great Falls, MT | Cascade | Dec 20, 11:05 p.m. MST | NWS TFX | NWS employee | UP TO 1 TENTH OF AN INCH ICE ACCUMULATION DUE TO FREEZING RAIN. |
| 0.10″ | Conrad, MT | Pondera | Dec 21, 12:00 a.m. MST | NWS TFX | Law enforcement | CONRAD POLICE DEPARTMENT REPORTED ABOUT 0NE TENTH OF AN INCH ICE ACCUMULATION DUE TO FREEZING RAIN. NUMEROUS SLIDEOFFS REPORTED ACROSS PONDERA COUNTY. |
| 0.01″ | 1 NE Simms, MT | Cascade | Dec 20, 9:35 a.m. MST | NWS TFX | Co-op observer |
Day: the 24 hours ending at 16:00 UTC (11 a.m. EST, 10 a.m. CST) on December 21, 2009, so morning observations count toward the day they end. Ice is the thickness of ice on surfaces as measured by the observer; reports of a trace (0.00″) are left out.
Spotter reports: National Weather Service Local Storm Reports (LSRs): measurements sent to NWS offices by trained storm spotters, CoCoRaHS and co-op observers, NWS staff, the public and others, archived by the Iowa Environmental Mesonet (Iowa State University). Reports are what each observer measured at one spot, often a storm total so far, and the NWS doesn't quality-check every one. Exact repeats count once.