Why Are There More Tornadoes This Year?
MELISSA BLOCK, host:
Those tornadoes yesterday struck a huge swath of the southern United States. Greg Carbin is a meteorologist at the National Oceanic and Atmospheric Administration's Storm Prediction Center. That's in Norman, Oklahoma.
Mr. Carbin, as you were watching these storms develop yesterday, saw the huge numbers of tornadoes striking, what was going through your mind as a meteorologist?
Mr. GREG CARBIN (Meteorologist, NOAA Storm Protection Center): Well, it was rather disturbing, first of all, to see the intensity of these storms moving across populated areas of the South. And then it's sad to see the results today and our sympathy goes out to those who are suffering through this and it will be many days for recovery. It was one event that I have not experienced before in 25 years of forecasting and it was quite stunning.
BLOCK: Never seen this before in 25 years?
Mr. CARBIN: Not to the extent we experienced yesterday. And I would say that most of the forecasters I worked with yesterday were just sort of glued to the radar and astonished at what we were seeing.
BLOCK: Was it the number of storms or the strength of them, the course that they were taking?
Mr. CARBIN: All of those, really. We knew well in advance. I mean, we had been watching this system for may days and advertising that in our outlooks and our watches. In fact, the watches issued yesterday were out two, three hours prior to the most devastating storms. But when you have not gone through something like this in your career, it is really pretty remarkable.
BLOCK: This, of course, follows a whole series of really violent storms this month. Is April setting a record?
Mr. CARBIN: It appears as if April 2011 will go down in the record books with the most tornadoes observed. We're carrying about 600 for the month, which is an unheard of figure when you go back through the past.
BLOCK: What would it have been, say, last year?
Mr. CARBIN: Well, a normal April over the last 10 years experiences roughly 160 to 180 tornado events for the entire month. And so, to see 500, 600 tornadoes in the month of April is really unprecedented.
BLOCK: And it's not over yet. Well, what accounts for that?
Mr. CARBIN: What's interesting about this April is that you've combined the typical springtime severe weather increase that we see in April and May with a very active jet stream pattern across the United States and sort of a stagnant jet stream pattern that supports development of deep low pressure systems day after day, very closely on the heels of one another. And that combination is a very dangerous and volatile one.
BLOCK: A lot of people would be wondering whether climate change has a role to play in what we're seeing with these tornados.
Mr. CARBIN: It's unlikely. We do not know. I mean, the short answer on that is that we simply don't know - that the record is not long enough to establish any trends. We see some years that are very quiet with respect to tornadoes and other years like this that are, you know, off the charts, so to speak.
BLOCK: Well, Greg Carbin, as you look forward at the weather patterns that you see developing, what do you see? Are we still in the thick of the tornado season and do you expect a lot more like this?
Mr. CARBIN: Well, one thing we can look at is the number of tornadoes in the past that have happened during the month of April and compare those to the number of tornadoes that occurred during the month of May. And when we look at that, we see very little connection between an active April and an active May. So we can hope that perhaps we will begin to see a change in this very active pattern.
Although, May is usually the busiest month of the year for severe weather and tornados. So it's not like we will not experience tornadoes in May, but we can certainly hope it's less than what we saw in April.
BLOCK: Greg Carbin, thanks for talking with us today.
Mr. CARBIN: Thank you.
BLOCK: Greg Carbin is a meteorologist with the National Oceanic and Atmospheric Administration's Storm Prediction Center.
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