Hurricane Florence battering the Southeast, a typhoon killing dozens in the Philippines, a California blaze taking a Utah firefighter's life - the weather's been surprising all summer.
In Utah too. Drought's fueled fires that have burned twice the acreage Utah usually sees in an entire year. And the water shooting down the Virgin River in an August flashflood was 150 times greater than normal. As summer ends, National Weather Service Hydrologist Brian McInerney spoke with Judy Fahys about the science behind this wild Utah weather.
Some questions and responses have been edited for length and clarity.
McInerney: What we've seen are long periods of high pressure followed by intense thunderstorm activity, wild flash floods, severe thunderstorms, lightning. You talk to people, and they haven't seen lightning like this. But when you step back from all this and you say, 'What's going on?' When you look at the [climate] research that's been done for a warming climate, this is what they talk about: long periods of high pressure followed by very intense weather, intense thunderstorm activity. And we're going to see more of this probably through September.
The problem with that is we're bringing more and more people into southern Utah that are not aware of this dynamic, and it's quite hazardous. We're lucky we haven't had fatalities this year.
Fahys: If you average it out, if you look at it over a year, it might seem like we got plenty of rain this year. But it doesn't really sound like that's the way it's going. So, help me sort that out.
M: These intense events that move across the landscape put down, you know, phenomenal amounts of rain, very intense rain, very intense thunderstorm activity, and we all measured the precip (precipitation) and then we compare it to the 30-year average. And you say, well, you're average for this year. But the problem is it came in a day, it came in an hour, and produced all this flash floods and kind of messiness. Whereas, what you hope for is more frequent storms but less intense, something [where] you're going to get rain every day. Kind of nice and that's a good thing. So, I think over time this pattern is going to increase. It's increasing now as we speak, and it's only going to get worse as we continue to warm.
F: It sounds like the pattern is for less predictability.
M: How we consider normal is a 30-year period. And that 30-year period jumps 10-years at the end of each 10-year period. When you look at each successive jump, what you find is we're getting hotter and we're getting drier throughout Utah, and the storm intensity is greater. We see storms that are much more … nasty in their in their realm and produce a lot more rain in a shorter period of time. We see winter storms that are less frequent but more intense. The precipitation across the Wasatch, for the most part, has pretty much been the same, but it's evolving from snow to rain during the winter months. And the storms are less frequent, but they're more intense when they get here. Winter storms — you don't see them as much, but when they do get here, they're pretty intense. We're seeing that in all forms of weather so the question is how do you forecast for this?
F: The way I kind of think about the changing climate is [that] I think about changing energy. The energy that used to be locked up in a lump of coal is now essentially in the air, and that's holding more rain and that's moving things around more. It's just basically changing fundamental patterns of our climate.
M: Yeah. We've taken carbon out of the rocks and from the ground, and we've put that in the atmosphere. And that extra carbon, CO2, what it does is it absorbs the heat coming out at night that usually goes back into space to some degree and re-radiate back in the atmosphere. It's like putting a blanket over the Earth. That the greenhouse has always been here, and it keeps us alive and it's a great thing, but now what we've done is made our blanket a little thicker. And now the heat at night can't get out into space. It stays in the atmosphere. And the question is how do we get it back in the rocks. Well, we're not going to do that.
F: So, when people say the climate has always been changing, you would say ...
McInerney: …The climate has always been changing, but it changes over thousands of years. We're changing it in 30 years. That's the difference. It's changing so fast, and we're trying to keep up with it.
F: How would you say we can see that in Utah, this change in climate?
M: I think with Utah what we notice are the winters are starting later. They're ending a little earlier. We're seeing more rain in November, October — months that we didn't see before. We also see winter storms that are not as frequent but they're more intense when they do get here. Anecdotally, we're seeing more intense rainfall events in southern Utah that are causing bigger flash floods. I think if you look throughout the entire country you see that, but this is just from my perspective of being with the National Weather Service. And the temperatures are hotter. We break heat records all the time, and that's just something when we do the climate at the weather service, that's the first thing we see we're breaking heat records frequently where you rarely see any kind of cold records if any. All of the research that the climate scientists have been talking about is actually occurring as we speak.
