John Allen, Ph.D., Associate Professor of Meteorology at Central Michigan University answered some common questions, especially after a storm that produces several tornadoes.
PREVIOUS COVERAGE: Multiple tornado touchdowns in SW Michigan, extensive damage reported
Why do we see damage on one side of the street, but not the other?
- A tornado's windfield can range from just a meter to several miles. It's a very concentrated field of wind, and winds rapidly accellerate. These winds are relatively confined. That's why one area may be hit, but another isn't.
- It's also why debris can be picked up by tornadoes - that's what causes the most injuries.
Are multiple tornadoes at the same time or in succession unusual?
- It's not uncommon to see tornadoes in clusters like we did on May 7.
- We had a warm front, which acted as the focus of where most of these storms started to produce tornadoes. It was a rapidly escalating environment, along with many supercells moving into West Michigan at once.
- We've had big numbers of tornadoes in teh southern part of the state before, but it's been a couple of decades since we've seen a storm like this.
The Science behind Tuesday's tornadoes part 2
What role did the storm spotters play in identifying these tornado locations?
- Storm spotters can submit a report to the National Weather Service through their website or by phoen call. There are NWS people who monitor that information to make sure what they're sharing is the most up-to-date information.
- Radar can tell us a lot about the potential for a tornado to be there, but on the ground reports makes sure we can be absolutely certain.
- That can actually lead to higher level warnings.
- We saw the first tornado emergency in Michigan on May 7. It's a relatively rare category reserved for a strong tornado moving into a relatively populated area.
What conditions lead to the perfect storm to spawn multiple tornadoes?
- Tornadoes tend to be relatively clustered. Conditions that favor them tend to favor relatively small areas. In this case, we had a warm front that was draped over the southern part of the state. As the storms approach the warm front, those conditions along the warm front, the winds change from east at the surface to southwesterly or westerly aloft. The change in wind direction and speed with height is what tornadoes really need in low levels of the atmosphere. So as the storms interacted with this front, that's what lead to the production of quite a few tornadoes in a relatively small period of time.
Other warnings about tornadoes:
- Tornadoes are often hidden or 'rain-wrapped.' It can make them hard to see until they're right in front of you. That's why it's so important to heed warnings, even if you dont' directly see something.
