Three Things to Know: US Midwest Severe Weather Outbreak – June 13-15

More than approximately 4 million single-family homes experienced 60 mph or greater wind speeds during the June 13 severe thunderstorm outbreak, with localized gusts exceeding 90 mph. Hundreds of thousands of homes are without power while record setting heat index values are recorded across the country.

1.      Severe weather was reported across the northern Midwest, including multiple derechos and tornadoes

• Severe thunderstorms and tornadoes were reported across the northern Midwest in the states of Wisconsin, Illinois, Indiana, Michigan and Ohio during the week of June 13. Two separate derechos that stretched from Wisconsin to West Virginia were recorded. Record settings gusts of 98 mph were recorded in Fort Wayne, Indiana and 84 mph at O’Hare International Airport outside Chicago, Illinois (Fig. 1).

Figure 1: Wind speed map of the June 13 severe thunderstorm outbreak.

• Multiple tornadoes touched down in the towns of Tomah (Fig. 2A), Mauston (Fig. 2B) and White City (Fig. 2C) in Wisconsin on June 15.

Figure 2: June 15 tornado footprints in Tomah (A), Mauston (B) and White City (C).

2.       Severe thunderstorm-generated winds can cause hurricane-like damage

• Hurricane-strength (>74 mph) gusts were reported across the affected states with some gusts surpassing 90 mph. Gusts of this strength can result in material property damage.
• Preliminary data shows over 4 million single-family homes (SFHs) may have experienced wind speeds of at least 60 mph, with a total reconstruction value (RCV) of $1.3 bn. See Table 1 below for a breakdown of SFH count and total RCV by state and windspeed band. This valuation is structure only.

• 90+ mph gusts were recorded in parts of Allen County, Indiana surrounding Fort Wayne.
• Light damage to homes in Tomah, WI and the Mile Bluff Medical Center in Mauston, WI were recorded. Trees and downed powerlines are prevalent across the affected areas.

3.       Dangerous heat waves and power outages have potential for life-threatening conditions

• Wide-spread power outages were reported across the Midwest. More than 540k outages have been reported across Ohio (320k), West Virginia (56.6k), Indiana (50.9k), Michigan (20.0k) and Illinois (19.0k).¹
• The National Weather Service has issued Extreme Heat Warnings across the Midwest. Heat Index values of over 100 degrees expected in some states. Those susceptible to heat-related illnesses and without the ability to cool should take extra precaution while emergency services repair systems across the Midwest.

• Downed powerlines and trees may impact emergency services ability to restore power.

¹ The Weather Channel [@weatherchannel]. Twitter, 14 June 2022.