Ice Storm — Carroll, Iowa

2009-12-23 · Carroll, Iowa

Wider weather episode

Part 1 of 2: A major winter storm system affected the central U.S. during Christmas week. There were two upper level systems involved with this storm. The southern stream low dove into the southern U.S. and then turned northeast. The turn was sharper than is typical as the northern stream upper low pushed southeast. The southern stream and polar low interacted with each other, resulting in a Fuji Wara effect. The southern low turned north, then eventually northwest and moved from northern Louisiana into Iowa. This resulted in a considerable amount of warm air being drawn north over Iowa. Cold air remained in place at the surface due to an existing deep snow cover over most of the state and a polar high pressure over western Ontario. Freezing rain broke out on the morning of the 23rd over west central Iowa, and spread into the north central counties by the afternoon of the 23rd. Freezing rain continued through the rest of the day, tapering off during the early morning hours of the 24th. To the north of the freezing rain area, 3 to 5 inches of snowfall occurred. Much of the area received one quarter to one half inch of ice. The hardest hit areas were from Audubon and Guthrie Counties, north into Carroll, Calhoun, and parts of Crawford Counties. At one point, reports indicated that power was out in 65% of the homes in Audubon, Crawford, and Carroll Counties. These areas received in excess of 1 inch of freezing rain. Tree and power line damage was widespread in these areas. Over 10,000 customers lost power in these counties, some for several days. Farther to the north and east there was damage with patchy power outages, but the damage was not as severe as to the southwest. Driving conditions were treacherous through the entire area with accidents and spin-outs too numerous to mention.

Source: NOAA Storm Events Database, event_id 200322. Narrative written by the NWS forecast office that issued the report.