Active Warnings
0
Refreshing...
Loading tornado data...
Loading tornado data...
Complete tornado information for Johnson County, Iowa - from real-time warnings to historical data and comprehensive statistics dating back to 1950.
Last updated: Never
Real-time tornado warning information for Johnson, Iowa with up-to-the-minute updates from the National Weather Service.
Active and expired tornado warnings in Johnson, Iowa for 2025
Detailed tornado warnings for Johnson, Iowa
Loading active warnings...
Comprehensive database of tornado events in Johnson, Iowa recorded since 1950 through the end of 2024(45 total records)
Total Tornados
45
Total Deaths
1
Total Injuries
51
Property Damage
$30.0M
Avg Length
4.9 mi
Avg Width
144 yd
Detailed charts and visualizations revealing tornado patterns by intensity, seasonality, and impact. These analytics show historical trends and unique characteristics of tornado activity in this region.
Shows tornado frequency across different months of the year, highlighting seasonal patterns. This information helps identify peak tornado seasons and periods of heightened risk.
Tracks tornado occurrences and fatalities over time, revealing long-term patterns and significant events. Toggle the injuries data to see additional impact metrics.
Visualizes the financial impact of tornadoes across years using a square root scale. This approach ensures both major damage events and smaller impacts are visible on the same chart.
Shows the breakdown of tornadoes by intensity rating (EF/F scale). This distribution helps understand the prevalence of different tornado strengths and their relative frequency.
Summary: In JOHNSON County, Iowa, Rating 1 tornadoes are the most common, comprising 39.5% of all recorded events. Weak tornadoes (Rating 0-1) account for 71% of all events, while strong tornadoes (Rating 2-3) make up 27%. There have been no recorded violent tornadoes (Rating 4-5) in this region.
Interactive map showing the paths and touchdowns of all recorded tornado events. Explore the spatial patterns and identify frequently affected areas.
Click on a tornado path to view detailed information. Paths are colored by intensity:
Loading map...
Comprehensive chronological list of all tornado events with detailed information on each occurrence. View specifics about intensity, damage, casualties, and timing for individual tornado events.
Tornado intensity is measured on two scales (learn more about tornado intensity scales):
| Rating | F Scale (1971-2007) | EF Scale (2007-Present) | Wind Speed Difference |
|---|---|---|---|
| 0 | F0: 40-72 mph | EF0: 65-85 mph | EF0 has higher minimum speed (+25 mph) |
| 1 | F1: 73-112 mph | EF1: 86-110 mph | EF1 has higher minimum (+13 mph), lower maximum (-2 mph) |
| 2 | F2: 113-157 mph | EF2: 111-135 mph | EF2 has lower maximum speed (-22 mph) |
| 3 | F3: 158-206 mph | EF3: 136-165 mph | EF3 has significantly lower speeds (-22 to -41 mph) |
| 4 | F4: 207-260 mph | EF4: 166-200 mph | EF4 has drastically lower speeds (-41 to -60 mph) |
| 5 | F5: 261-318 mph | EF5: >200 mph | EF5 has significantly lower threshold (-61 mph) |
Why the Wind Speed Differences? Research showed the original F-Scale overestimated wind speeds needed to cause specific damage.
Key Improvements in the EF Scale:
For historical consistency, this website groups equivalent ratings together (e.g., both F3 and EF3 tornadoes are considered in the same intensity category despite their significant wind speed differences).