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Storm Events Database
Event Details
| Event | Hail |
| Magnitude | 0.75 in. |
| State | IOWA |
| County/Area | GRUNDY |
| WFO | DMX |
| Begin Date | 05/12/2010 18:18:00 CST-6 |
| Begin Range | 3 |
| Begin Azimuth | SW |
| Begin Location | ZANETA |
| Begin Lat/Lon | 42.37/-92.59 |
| End Date | 05/12/2010 18:18:00 CST-6 |
| Deaths Direct/Indirect | 0/0 (fatality details below, when available...) |
| Injuries Direct/Indirect | 0/0 |
| Property Damage | 0.00K |
| Crop Damage | 0.00K |
| Episode Narrative | A strong upper level low pressure trough over the western U.S. moved into the central states during the day on the 12th. The situation was quite similar to the event 2 days prior, though the severe weather was farther north. The 850 mb front was stretched across Iowa, with a strong surface front south of the state. A significant cool layer was in place over Iowa with surface temperatures remaining in the 40s through the day. Significant instability was in place south of Iowa with most unstable CAPE values of 1000 to 2000 J/kg in place. A considerable amount of moisture was transported north into the central U.S. on a 60 kt low level jet. Precipitable water values were between 1.5 and 1.75 inches. The freezing level was in the 12,000 to 13,000 foot range. CAPE in the -10 to -30 C layer of the atmosphere was between 100 and 400 J/kg. There was significant shear present, with the effective shear around 60 kts. Thunderstorms formed during the predawn hours of the 12th and moved across Iowa during the morning of the 12th. Once these storms moved out, another area of thunderstorms formed along the 850 mb front. Most of the storms produced hail up to dime size. Some of the stronger thunderstorms produced quarter size hail with one producing 1 1/4 inch diameter hail in Marshall County. Several of the storms also produced large amounts of hail, with reports of the ground being covered by hail. Successive rounds of thunderstorms continued to push into central and northeast Iowa. Most hail was below the size of quarters from the late afternoon rounds. Heavy rain became a problem with spotty flash flooding reported. Flooding took place in Butler County due to rainfall of nearly 3 inches that fell just a day after a general 1 to 2 inch rainfall occurred. Flooding was largely limited to agricultural lands. In Polk County, heavy rainfall of around 2 inches fell after the area had received about an inch in the 36 hours prior. Flash flooding occurred on the east side of the Des Moines metropolitan area. A ramp on Highway 65 was flooded by high water and an intersection southeast of Altoona was washed out. As the storms moved through the Wavery area, lightning struck a house causing s small fire. It was extinguished quickly, resulting in little damage. |
| Event Narrative |
All events for this episode:
| Location | County/Zone | St. | Date | Time | T.Z. | Type | Mag | Dth | Inj | PrD | CrD |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Totals: | 0 | 0 | 92.00K | 0.00K | |||||||
| BRAYTON | AUDUBON CO. | IA | 05/12/2010 | 12:33 | CST-6 | Hail | 0.75 in. | 0 | 0 | 0.00K | 0.00K |
| BLAIRSBURG | HAMILTON CO. | IA | 05/12/2010 | 13:07 | CST-6 | Hail | 0.88 in. | 0 | 0 | 1.00K | 0.00K |
| BLAIRSBURG | HAMILTON CO. | IA | 05/12/2010 | 13:07 | CST-6 | Hail | 0.88 in. | 0 | 0 | 3.00K | 0.00K |
| STATE CENTER | MARSHALL CO. | IA | 05/12/2010 | 13:15 | CST-6 | Hail | 1.25 in. | 0 | 0 | 10.00K | 0.00K |
| BAGLEY | GUTHRIE CO. | IA | 05/12/2010 | 13:31 | CST-6 | Hail | 1.00 in. | 0 | 0 | 5.00K | 0.00K |
| DOWS | WRIGHT CO. | IA | 05/12/2010 | 13:35 | CST-6 | Hail | 0.75 in. | 0 | 0 | 0.00K | 0.00K |
| COULTER | FRANKLIN CO. | IA | 05/12/2010 | 13:37 | CST-6 | Hail | 1.00 in. | 0 | 0 | 3.00K | 0.00K |
| COOPER | GREENE CO. | IA | 05/12/2010 | 13:48 | CST-6 | Hail | 1.00 in. | 0 | 0 | 3.00K | 0.00K |
| TRAER | TAMA CO. | IA | 05/12/2010 | 13:54 | CST-6 | Hail | 1.00 in. | 0 | 0 | 5.00K | 0.00K |
| BEAVER | BOONE CO. | IA | 05/12/2010 | 14:09 | CST-6 | Hail | 1.00 in. | 0 | 0 | 5.00K | 0.00K |
| RIDGEPORT | BOONE CO. | IA | 05/12/2010 | 14:38 | CST-6 | Hail | 1.00 in. | 0 | 0 | 3.00K | 0.00K |
| ARBOR HILL | ADAIR CO. | IA | 05/12/2010 | 15:23 | CST-6 | Hail | 1.00 in. | 0 | 0 | 3.00K | 0.00K |
| ALLEMAN | POLK CO. | IA | 05/12/2010 | 15:30 | CST-6 | Hail | 1.00 in. | 0 | 0 | 5.00K | 0.00K |
| MARSHALLTOWN ARPT | MARSHALL CO. | IA | 05/12/2010 | 17:52 | CST-6 | Hail | 1.00 in. | 0 | 0 | 3.00K | 0.00K |
| MARSHALLTOWN ARPT | MARSHALL CO. | IA | 05/12/2010 | 17:55 | CST-6 | Hail | 0.88 in. | 0 | 0 | 1.00K | 0.00K |
| ZANETA | GRUNDY CO. | IA | 05/12/2010 | 18:18 | CST-6 | Hail | 0.75 in. | 0 | 0 | 0.00K | 0.00K |
| KNOXVILLE | MARION CO. | IA | 05/12/2010 | 18:40 | CST-6 | Hail | 0.75 in. | 0 | 0 | 2.00K | 0.00K |
| ALTOONA | POLK CO. | IA | 05/12/2010 | 19:00 | CST-6 | Flash Flood | 0 | 0 | 25.00K | 0.00K | |
| WASHBURN | BLACK HAWK CO. | IA | 05/12/2010 | 19:22 | CST-6 | Hail | 0.75 in. | 0 | 0 | 0.00K | 0.00K |
| HASTIE | POLK CO. | IA | 05/12/2010 | 19:30 | CST-6 | Flash Flood | 0 | 0 | 5.00K | 0.00K | |
| WAVERLY | BREMER CO. | IA | 05/12/2010 | 20:05 | CST-6 | Lightning | 0 | 0 | 5.00K | 0.00K | |
| CLARKSVILLE | BUTLER CO. | IA | 05/12/2010 | 22:52 | CST-6 | Flash Flood | 0 | 0 | 5.00K | 0.00K | |
| Totals: | 0 | 0 | 92.00K | 0.00K |
