Thunderstorm Wind — Steele, North Dakota

2007-07-15 · near Finley, Steele, North Dakota

Event narrative

Fully grown trees were uprooted. Some trees fell on power poles and powerlines, causing power outages in Finley. Trees also fell on cars and damage was reported at the grain elevator. On one house porch, the windows were blown out and the screens were torn off. Extensive wind driven hail produced crop damage across portions of Finley Township.

Wider weather episode

At 3 pm CST on the 15th, a stationary front was located from near Minot (ND) to Jamestown (ND) to near Sisseton (SD). South of the front, mid afternoon temperatures ranged in the mid 80s to lower 90s. To the north of the front, a meso-high had formed, with much cooler and drier air around it. The temperature across the boundary ranged from 89F at Minot, to 73F at Devils Lake, to 64F at Crookston. The upper air pattern had a western ridge and an eastern trough, putting the northern plains in northwest flow aloft. A strengthening upper jet also moved toward eastern North Dakota, giving this system good surface and upper level support.

A supercell thunderstorm developed over southern Steele County around 530 pm CST and tracked across western Cass County and into eastern Ransom County before weakening after 7 pm CST. Then, another supercell thunderstorm formed over northern Steele County around 725 pm CST. This storm tracked just west of the path of the first storm, again mainly hitting central Steele County, western Cass County, and eastern Ransom County, before weakening around 915 pm CST. Both thunderstorms tracked south-southeast at speeds between 40 and 50 mph and spawned multiple tornadoes which were embedded within the overall downburst wind and hail pattern.

The significant downburst wind and wind driven hail was seen in two partially overlapping paths, with each path from 5 to 7 miles wide and between 60 and 80 miles long (this damage path showed up clearly on satellite images). The strength of these winds is believed to have exceeded 80 mph with speeds over 100 mph in some localized areas. Hail sizes ranged from penny to hen egg sized.

Most areas received considerable hail damage at the same time as the strong winds. Law enforcement officials and witnesses stated that the hail often persisted for longer than 5 minutes and completely covered the ground. The hail damaged roofs, windows, and siding in many homes along the damage path. Stripped and decimated corn, bean, and wheat fields were typical along the entire storm path too. The ND Farm Service Administration estimated losses occurred on over 700,000 acres in five counties. Total crop losses may exceed $250 million, with other property losses from $15 to $20 million. Cass and Steele Counties received a Presidential Disaster Declaration.

View location on OpenStreetMap → (47.5200, -97.8500)

Source: NOAA Storm Events Database, event_id 48343. Narrative written by the NWS forecast office that issued the report.