A powerful storm system moved through the central United States last week causing everything from blizzards, to record flooding, to tornadoes. Unfortunately, Michigan experienced the tornadic severe weather part of the storm.
When all was said and done four tornadoes tore through parts of Shiawassee and Genesee Counties. The storms raged hardest between 6:45 p.m. and 7:45 p.m. Thursday night. There were three EF-0 rated tornadoes and one EF-2. The stronger tornado caused significant damage between Bancroft and Vernon.
The science: The storm packed a powerful low level jet (LLJ) which packed winds of over 100 mph. A LLJ is a fast moving current of air around 10-12 thousand feet above the ground. This current of air brings in warmth and moisture from the Deep South, ingredients needed for thunderstorms. A LLJ is often associated with severe weather as it provides the needed atmospheric dynamics the storms thrive off of.
The first batch of storms moving through early in the afternoon had storm motions of over 100 mph to the northeast as they rode the LLJ. This was also noticeable earlier in the day as clouds raced across the sky. The 100 mph winds in the LLJ did not translate to the surface, however. Surface wind speeds were around 40-50 mph.
As the LLJ moved east and the cold front moved in, a second line of thunderstorms developed. This is the line that would bring the tornado threat. The atmosphere was primed with what we call “shear.” This is the rotation of winds with height in the atmosphere. There was enough in lower levels to support strong tornadoes.
The storms moved east into the favorable environment in place over Shiawassee and Genesee Counties and produced the dangerous tornadoes. Here are the survey reports conducted by the National Weather Service for all four touchdowns:
TORNADO #1 – SSW of Corunna, MI
“The tornado touched down close to the intersection of Bennington Greens Drive and Innsbrook Drive, snapping pine trees. The tornado continued northeast, crossing M-52 near West Grand River Road. Hardwood trees were observed snapped with large limbs down. The tornado then hit a Farm along South Morrice Road, just south of W Garrison Road. Trees were uprooted and a well built farm outbuilding lost its roof. The tornado snapped additional trees near Vandecarr and Bennington Roads before lifting near the Maple River.” – NWS Detroit.
Rating: EF-0
Winds: 80 mph
Path Length: 6.4 miles
Funnel Width: 100 yards
TORNADO #2 – Vernon, MI
“The tornado touched down around the intersection of Britton Rd and I-69 and produced EF-0 damage up to Bancroft Rd and Newburg Rd with large tree limbs downed and trees snapped. Shoreline Lake Condos had over 10 trailers and mobile homes damaged from falling trees. The tornado continued northeast from Bancroft Rd/Newburg Rd to M-71 just ESE of Vernon producing EF-2 damage. One roof was completely taken off, a second story wall collapsed, and numerous homes with wall damage. The tornado weakened back down to EF-1 as two more home damaged near Bennington Rd Reed Rd. The tornado finally lifted near Riniel Rd just south of Lytle Rd.” – NWS Detroit.
Rating: EF-2
Peak Winds: 125 mph
Path Length: 18.2 miles
Funnel Width: 250 yards
TORNADO #3 – Flushing, MI
“The tornado touched down on Nichols Rd just south of Corunna Rd before traveling east/northeast to Calkins Rd just east of Morrish Rd. Damage included downed and snapped trees, large limbs, and a collapsed pole barn. The tornado lifted near Jennings Rd just north of Pasadena Ave.” – NWS Detroit.
Rating: EF-0
Peak Winds: 85 mph
Path Length: 8 miles
Funnel Width: 75 yards
TORNADO #4 – Genesee Township, MI
“A tornado touched down near the intersection of Stanley and Bray Roads and quickly tracked off to the northeast. The storm lifted near the M-57 and Irish Road intersection. The tornado was strongest when it hit the Camelot Villas off of Genesee Road. A mobile home was flipped onto its side, with another mobile home partially blown off the foundation. Roof and siding damage was prevalent within the mobile park. Clusters of trees were snapped and tree tops sheared along the tornado path, with a couple other small trailers flipped.” – NWS Detroit
Rating: EF-0
Peak Winds: 80 mph
Path Length: 6.5 miles
Funnel Width: 75 yards