This has been the year of sudden start to Atlantic hurricane season, among other oddities (not to mention the deadly pandemic). So perhaps it shouldn’t be surprising that Lake Superior is set to see its first post-tropical cyclone ever recorded, and yet here we are.
Tropical Depression Cristobal is currently churning over the Midwest after bringing torrential rain and storm surge to the Gulf Coast. It’s in the process of becoming subtropical but is expected to maintain its swirling characteristics and make landfall on Lake Superior (or is it lakefall?). While the lake is no stranger to massive storms and powerful gales, it’s never experienced one like Cristobal.
The U.S. National Hurricane Centre stopped issuing forecasts for Cristobal early on Tuesday morning, and it issued its final forecast map on Monday. But that map showed the storm heading in a very weird direction.
Tropical Storm Cristobal spun up on Tuesday in the Gulf of Mexico. It's the third tropical cyclone of the Atlantic hurricane season that only officially began on Monday, and marks the earliest third storm on record.Read more
Over the next 24 hours, the storm is forecast to continue running through the heart of the Midwest into Wisconsin and Michigan’s Upper Peninsula. By Wednesday morning, Cristobal is poised to make a second landfall on Lake Superior somewhere in the vicinity of the tiny community of Copper Harbour, Michigan. It’s shades of 2018’s Tropical Depression Alberto, a pre-season tropical cyclone that made lakefall on Lake Michigan, a first-ever occurrence.
Cristobal won’t maintain its tropical characteristics all the way to Superior. It should transition to post-tropical cyclone, a type of “cyclone that no longer possesses sufficient tropical characteristics,” according to the National Hurricane Centre. It could also scoop up some energy from the storm system blowing out of the West that brought whiteout snow to Montana and fire danger to the Southwest, creating a huge, swirling mess of a storm.
But if it continues to spin as cyclones do and maintains its current trajectory, Cristobal would be the first tropical or post-tropical cyclone to make landfall on Lake Superior on records that go back to the mid-1800s. The storm is actually forecast to strengthen after that and could make yet another landfall on Hudson Bay in Canada (bayfall?), something that’s happened only one other time, in 1954, when the post-tropical storm version of Hurricane Hazel reached the bay.
The weirdness is the biggest story of Cristobal, though the impacts on the Great Lakes are also nothing to scoff at. The National Weather Service has issued a gale warning for Lake Superior and Lake Michigan, calling for winds of up to 74 km/h, a shade below the 80 km/h winds it brought to the coast of Louisiana when it made landfall on Monday. It could also whip up 3.05 m waves on the lakes and even kick up a few tornadoes in the Ohio and Mississippi River Valleys.
The Great Lakes have seen their fair share of intense storms, though fall is generally when they form and come out of the west. The contrast of cold Arctic air and warm Gulf of Mexico can drive their formation in shadow of the Rockies before they swing over the lakes and intensify by feeding on relatively warm waters, according the National Weather Service. Intense gales have stirred up massive waves and even sunk large ships, including the the Edmund Fitzgerald in November 1975 that’s been immortalised in a Canadian folk song by Gordon Lightfoot.
All this makes Cristobal a continued meteorological oddity of the highest order. It’s the earliest third named storm ever recorded in the Atlantic and came to the basin via the Pacific, where it was Tropical Storm Amanda, the first named storm of the season in that basin. Cristobal follows Arthur and Bertha, two tropical storms that formed before the season even officially began on June 1. Hurricane season is forecast to be an active one and run until November 30, so there’s unfortunately still plenty of time to set more weird milestones.