As Texas recovers from the extreme weather events that took place last week, social media sites are divided on the cause of the weather. Some say it is a result of climate change and some say it is something that happens every now and then. Texas Tech professors weighed in on the debate.
According to the National Weather Service, a jet stream is a narrow band of strong wind in the upper level of the atmosphere that is built on where the strongest gradient in temperatures is.
Anne Stoner, a research professor with the Tech Climate Center, said there has been a lot of warming happening in the Arctic due to climate change, and when the Arctic heats up, there is not as big of a difference in temperatures of northern and southern latitudes.
This results in a reduction of the speed of the jet stream, Stoner said, which causes the jet stream to meander, when it meanders it gets dips, or troughs, where cold air comes down.
“It’s one of those pockets of air that has been allowed to come down because of the meandering jet stream, and that caused what we saw in Texas and most of the U.S.,” Stoner said.
Though the troughs and ridges are normal for the jet stream in the spring and summer, Stoner said it is unusual for it to happen in winter, when the jet stream is traditionally pulled tight to the arctic.
Brian Ancell, associate professor of atmospheric science, said it is normal for winter storms to come through Lubbock, bringing snow and low temperatures with them, but not as low as what was seen last week. However, he said occasionally these events happen.
For example, Ancell said if a dice is rolled, it will sometimes land on the number two, but it will not happen every time.
“That’s how the weather works too,” Ancell said. “You can think of it kind of like a distribution of events, some are more likely, which are the ones we usually get, and some are less likely, but they still happen.”
If climate changes, so does the weather, Ancell said. As it gets warmer, the jet stream changes, when that happens it changes how frequently weather systems happen in this area.
Though Ancell said there is certainly some connection between the extreme weather system in Texas and climate change, he said it is hard to understand with rare events, because they are rare. When extreme weather events become normal, it is more likely that climate change is the cause. There is not enough data to reliably say climate change is behind stronger winter storms or worse hurricanes.
“The normal situation is, you get extreme weather events once in a while, and that’s just what we got and that’s a normal situation,” Ancell said.
The system that moved through Texas and other parts of the U.S. was a large one, Ancell said. When there is a large ridge, it causes the pressure of the surface to be high, pushing the arctic air south. Every winter, Texas gets multiple of these arctic fronts, which is cold air pushed down from the northern U.S. and Canada that cannot make it over the Rocky Mountains and therefore pushes down through Texas.
“Those are the days we go from 70 degrees one day and then wake up the next morning and it’s like 25 degrees, and the high is 35,” Ancell said.
Sometimes these fronts are bigger, Ancell said, and the ridge is larger and cold air is already in place in the northern U.S., causing extreme winter weather.
All these things could have been happening independently and no one would have cared, Ancell said, it would have been cold in the northern U.S. but fine here.
“The fact that those things lined up is somewhat out of the ordinary, but again it’s not like, you couldn’t say it was because of climate change I don’t think,” Ancell said. “These things do happen together once in a while.”
It is not that climate change did not cause the system Ancell said, but it is something that cannot be determined until more data is gathered.
Donald Haragan, previous president of Tech, now retired, lives in Austin, and said he has never seen weather like this before and believes climate change either directly or indirectly influenced the storm.
“It was really devastating and really unusual,” Haragan said.
Climate change will cause events like this one to become less rare, Stoner said.
“It’s a combination of a rare event and climate change,” Stoner said.