IOWA, USA — The National Weather Service has released preliminary storm ratings for five Iowa tornadoes that hit on Tuesday, May 21.
That includes an EF-4 in Greenfield, an EF-3 in Adams County and an EF-2 that spanned both Polk and Story County. Preliminary ratings are pending further assessments and are subject to change.
Here is the data NWS has released so far.
The National Weather Service in Des Moines confirms the tornado in Greenfield was an EF-4, an upgraded rating from EF-3 earlier in the week.
An EF-4 tornado is characterized as a violent storm with devastating levels of damage. Wind speeds typically range between 166 and 200 miles per hour.
Four people in Greenfield were killed in the storm, plus one woman who died after her car was blown off a roadway near Corning, according to the Adams County Sheriff's Office. Monica Zamarron's death in Adams County happened during the same tornado that went through Greenfield and is separate from the tornado surveyed in northwest Adams County which is listed at the bottom of this story.
- Time: 2:57-3:43 p.m.
- Rating: EF-4
- Estimated Peak Winds: 175-185 mph
- Path Length: ~44 miles
- Max Width: 1,000 yards
- Time: 4:30-5:05 p.m.
- Rating: EF-2
- Estimated Peak Winds: 135 mph
- Path Length: 41 miles
- Max Width: 1,000 yards
Johnston High School was closed on Wednesday due to "extensive storm damage" from this tornado.
Story County officials said two people sustained non-life-threatening injuries in the storm.
NW Adams County
The NWS has preliminarily rated the tornado that swept through northwest Adams County as an EF-3.
The tornado reached an estimated peak wind speed of 150 miles per hour, with a path length of 32 miles and a maximum width of 1,300 yards.
- Time: 2:43-3:19 p.m.
- Rating: EF-3
- Estimated Peak Winds: 150 mph
- Path Length: 32 miles
- Max Width: 1,300 yards
SE Adams County
- Time: 3:19-3:33 p.m.
- Rating: EF-0
- Estimated Peak Winds: 85 mph
- Path Length: 12 miles
- Max Width: 50 yards
Red Oak
- Rating: EF-1
- Estimated Peak Winds: 107 mph
- Path Length: 3 miles
- Max Width: 70 yards
Buena Vista County
The National Weather Service office in Sioux Falls confirmed a brief EF-1 tornado touched down in Buena Vista County, northwest of Storm Lake.
- Time: 2:30-2:35 p.m.
- Rating: EF-1
- Estimated Peak Winds: 110 mph
- Path Length: 1.64 miles
- Max Width: 75 yards
Page County
- Rating: EF-1
Coburg (Montgomery County)
- Rating: EF-0
- Rating: EF-1
- Time: 3:09 p.m.-3:18 p.m.
- Estimated Peak Winds: 95 mph
- Path Length: 7.33 miles
- Max Width: 100 yards
- Rating: EF-2
- Time: 3:41 p.m.-3:56 p.m.
- Estimated Peak Winds: 115 mph
- Path Length: 11.87 miles
- Max Width: 200 yards
- Rating: EF-0
- Time: 4:25 p.m.-4:26 p.m.
- Estimated Peak Winds: 75 mph
- Path Length: 1.04 miles
- Max Width: 40 yards
- Rating: EF-0
- Time: 4:28 p.m.-4:32 p.m.
- Estimated Peak Winds: 75 mph
- Path Length: 2.01 miles
- Max Width: 75 yards