NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Shell Rock, IA
Every tropical system within 75 miles since 1851 and every tornado within 25 miles since 1950.
Data: NOAA NHC HURDAT2 and NOAA SPC tornado and hail reports, through 2025 · Updated
No tropical storm or hurricane has passed within 75 miles of Shell Rock, Iowa since records began in 1851. Since 1950, 113 tornadoes have touched down within 25 miles, 8 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 0
- Tornadoes
- 113
- EF3 or stronger
- 8
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
25 deaths in all
What the records show for Shell Rock
The highest rating among the 113 tornadoes within 25 miles is F5 or EF5, reached 2 times; the most recent, on May 25, 2008, came within 9 miles. The deadliest, an F5 on May 15, 1968, killed 13 people. Of the 113, 5 had paths within 5 miles of the city centre, and 59 have come since 2000. June has had the most tornadoes, 34. The most recent tornado was on August 18, 2025. Of the 241 Iowa cities on this site, 69% have more tornadoes within 25 miles than Shell Rock. Hail has been reported within 10 miles 107 times since 1960, with stones up to 4.5 inches (grapefruit size). Shell Rock has more hail reports within 10 miles than 63% of the 241 Iowa cities.
Compare Shell Rock's storm record with another city →
Tornadoes within 25 miles of Shell Rock
By decade
- 2020s16
- 2010s16
- 2000s27(2 EF3+)
- 1990s12(1 EF3+)
- 1980s11
- 1970s18(1 EF3+)
- 1960s11(3 EF3+)
- 1950s2(1 EF3+)
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| May 15, 1968 | F5 | 23 mi | 62.1 mi | 13 / 462 |
| May 25, 2008 | EF5 | 9 mi | 40.97 mi | 9 / 70 |
| Sep 1, 1961 | F4 | 10 mi | 26.6 mi | 0 / 7 |
| May 11, 2000 | F3 | 15 mi | 18.6 mi | 1 / 25 |
| Apr 16, 1960 | F3 | 25 mi | 29.8 mi | 1 / 5 |
| May 20, 1953 | F3 | 20 mi | 116.1 mi | 1 / 0 |
| Jun 28, 1990 | F3 | 25 mi | 9 mi | 0 / 0 |
| Nov 9, 1975 | F3 | 25 mi | 39.4 mi | 0 / 0 |
| Dec 15, 2021 | EF2 | 23 mi | 7.49 mi | 0 / 0 |
| Jul 14, 2021 | EF2 | 2 mi | 12.88 mi | 0 / 0 |
| Sep 6, 2001 | F2 | 2 mi | 11.5 mi | 0 / 0 |
| May 11, 2000 | F2 | 24 mi | 5 mi | 0 / 0 |
The strongest 12 of 113, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Shell Rock
The Storm Prediction Center has 107 hail reports within 10 miles of Shell Rock since 1960, made on 61 separate days. Of these, 66 were 1 inch across or larger, and 14 reached 2 inches. The largest size, 4.5 inches (grapefruit size), was reported on 2 days, most recently July 16, 2007. The most recent report is from September 16, 2025. June has the most reports, 32.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Shell Rock
The nearest NOAA station with 1991–2020 climate normals is Allison, IA, 11 miles west of Shell Rock at 1,038 feet. July is the warmest, with an average high of 83°F and low of 63°F; January is the coolest, at 25°F and 8°F. June is the wettest at 5.5 inches of precipitation on average and January the driest at 0.9 inches; the year adds up to 35.4 inches over 64 days with at least a tenth of an inch. Highs reach 90°F on about 12 days a year, almost all from June to September. Lows fall below freezing on about 150 nights a year. That 35.4 inches is more than at 37 of the 124 Iowa stations used on this site (30%). Waverly, 7 miles east, has its own station (Tripoli, IA): 38.7 inches a year, 3.3 more than here, and the same July average high, 83°F.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" |
|---|---|---|---|---|
| Jan | 25 | 8 | 0.9 | 3 |
| Feb | 29 | 12 | 1.0 | 3 |
| Mar | 43 | 24 | 1.8 | 5 |
| Apr | 59 | 36 | 3.8 | 7 |
| May | 70 | 49 | 5.1 | 9 |
| Jun | 80 | 59 | 5.5 | 8 |
| Jul | 83 | 63 | 4.2 | 7 |
| Aug | 80 | 60 | 4.0 | 6 |
| Sep | 74 | 51 | 3.4 | 6 |
| Oct | 61 | 39 | 2.5 | 5 |
| Nov | 44 | 25 | 1.8 | 4 |
| Dec | 31 | 15 | 1.4 | 3 |
| Year | 57 | 37 | 35.4 | 64 |
Averages for 1991–2020 at Allison, IA (1,038 ft), from NOAA NCEI U.S. Climate Normals. Normals describe the station; the farther a place is from it, and the bigger the difference in height, the more its weather can differ.
Floods, thunderstorm wind and lightning near Shell Rock
Since 1996, the National Weather Service has logged 176 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Shell Rock: 85 thunderstorm wind reports, 47 floods, 28 heavy rain events, 11 flash floods and 5 lightning strikes. They killed 0 people and injured 9, and the NWS estimated $30.6 million in property and crop damage. The strongest thunderstorm gust on record here was 81 mph, on September 21, 2007. May has had the most flash floods, 4 of 11. Of the 240 Iowa cities on this site with a flash flood on record, 95 have had fewer than Shell Rock.
July 20, 2019: thunderstorm wind 6 miles from the centre of Shell Rock — 9 injured, $20,000 damage.
June 12, 2010: flood 5 miles from the centre of Shell Rock — $20.0 million damage.
June 1, 2008: flood 5 miles from the centre of Shell Rock — $1.5 million damage.
Source: NOAA NCEI Storm Events Database, events whose starting point is on record, 1996 to June 30, 2026. Damage is the NWS estimate in the dollars of the year, not insured losses, and NWS notes that some reports are unverified.
Flood insurance claims, disaster declarations and FEMA risk ratings
Flood insurance policyholders in Shell Rock's ZIP code 50670 have filed 31 claims with the National Flood Insurance Program since 1993, and were paid $856,000 for buildings and contents, in the dollars of each year. The year with the most claims was 1999, with 10. 26% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 91 Iowa cities on this site with 10 or more claims, 42 have fewer than Shell Rock.
Butler County, which includes Shell Rock, has been named in 25 federal disaster or emergency declarations since 1965, 23 of them major disasters (by incident: 11 floods, 11 severe storms, 2 biological emergencies, 1 hurricane). The latest major disaster declaration was Severe Storms, Tornadoes, and Flooding, on May 24, 2024. FEMA's National Risk Index gives Butler County a Very Low rating for natural hazard risk overall; by hazard: Relatively Moderate for strong wind; Relatively Low for tornadoes, hail and inland flooding; Very Low for hurricanes, lightning and heat waves. It models the county's expected loss from all 18 hazards it covers at $14.5 million a year, the 39th highest of 99 Iowa counties; of the hazards above, the largest share, $7.1 million (49%), is from inland flooding.
Claims: FEMA, OpenFEMA Dataset FIMA NFIP Redacted Claims – v3, summed over ZIP codes; payments in the dollars of each year, not adjusted for inflation. Declarations: Disaster Declarations Summaries – v2, by county. Retrieved October 25, 2026. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Risk ratings: FEMA, National Risk Index county table, December 2025 (v1.20), retrieved October 26, 2026; ratings compare counties nationwide, are meant for planning and are no substitute for a local risk assessment. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
What counts as a pass, the distances and the sources: how this storm history is built.