Landspout tornado touches down near New Carlisle Sunday
Rain showers and thunderstorms came with a little extra for parts of Michiana on Sunday, as a tornado briefly touched down in a St. Joseph County farm field.
Storm spotters saw a weak, nearly-stationary tornado form around 3:45 PM Sunday northeast of New Carlisle. Meteorologists at the National Weather Service confirmed the tornado Monday.
Information on the brief touchdown of an EF-U tornado on Oct 3, 2021 near New Carlisle, IN. The image gives a brief breakdown of what a landspout is. https://t.co/XbzqF9F0WU pic.twitter.com/Bna7nzbzp2— NWS Northern Indiana (@NWSIWX) October 4, 2021
The twister did not produce any damage, so it was rated EF-U.
Tornadoes are rated on damage produced, not by wind speed. Any wind speed that you see assigned to a tornado is actually estimated based on the damage observed. So, if a tornado occurs in a spot where it doesn't produce any damage, it's classified as EF-U (U standing for undetermined).
This tornado also has another interesting classification: landspout. Landspouts are still considered tornadoes, but they form in a different way compared to the classic twisters you might see from severe thunderstorms. Cold air funnels (which sometimes lead to landspouts) occur when you have cold air aloft and warm air near the Earth's surface. That temperature difference can cause enough instability and can stretch an updraft enough to get funnel clouds to form.
These funnels aren't exactly rare, but they don't show up well on RADAR and aren't spotted that often. As a result, tornado warnings are not usually issued by the NWS in these cases. It's even more rare that these "cold-air funnels" reach the ground. The landspout near New Carlisle formed during the development of a shower along a boundary, which provided just enough ingredients for the brief twister to form.
As a cut-off low continues to circulate through the Midwest this week, keep an eye to the sky. More funnels and landspout tornadoes could form, especially toward Thursday.