At the start of spring, way back in early March, meteorologists saw the barrage of atmospheric rivers approaching California and foresaw the flooding that would follow. One meteorologist in particular, Kris Mattarochia, used the words “unprecedented” and “unparalleled” to describe the storm system during a press conference in Fresno. Those of us who live here know what happened next - severe flooding along rivers throughout the southern San Joaquin Valley, and the re-emergence of Tulare Lake for the first time in nearly 30 years.
Mattarochia is Science and Operations Officer with the National Weather Service in Hanford. And now, after much of what he and other meteorologists predicted came true, KVPR’s Kerry Klein sat down with him to talk about what can be learned from this winter, and how they knew it would be so extreme.
Listen to the segment in the player on this page, and read the transcript below.
KRIS MATTAROCHIA: So what happened is that we had a strong snowstorm occur at very low elevations, 1,000 to 4,000 feet.
MATTAROCHIA: It was about one to four feet of new snow that fell. And then the following week, there was a very warm storm that came through that produced several inches of rain on top of that fresh one to four feet of new snow. So much of that snow was going to melt and also the several inches of rain were going to run into the local waterways. So, considering we had all of this water and that we were already above average, this combination was something that was unparalleled in this area.
KERRY KLEIN: Yeah, and you had…a lot of your predictions really were eerily accurate. Maybe not eerie for you, eerie for those of us who are not meteorologists and don't have the power to predict these things. You also said at the time that this winter would compare to that of 1969, in terms at least of storms that might be in relatively recent memory. In the end, how did those two winters compare?
MATTAROCHIA: So actually, with regards to the amount of water stored in reservoirs, plus the water that was held in the snowpack, it was actually worse than 69. In 1969 Tulare County had several swift water rescues and homes washed away. Same thing happened with this season. Also in 1969 was a drought-deluge year. And then another similarity was that the Tulare Lake also emerged in 1969 similar to like it did this year.
KLEIN: How does it feel to know that you that you got this right in so many ways?
MATTAROCHIA: Well, I don't really consider myself right or wrong, because even though I can give a correct forecast, what I might deem is correct, if the public and our partners and everyone doesn't get the right message and take the right actions based upon that forecast, then that forecast really is of no value. All of us that want to protect life and property judge our performance on how well the message is received and how proactive folks are. And from that aspect of it, it went very well. I think everybody saw how unusual this was. When I said to people that there would be areas flooded that normally don't flood or have not flooded for 20 or 30 years, that really hit home with people and people were able to take precautions and prepare.
KLEIN: Yeah, I would imagine there is some psychology involved in how you communicate extreme weather events, especially if there is the potential for injury or death. And you yourself have experience in some parts of the world, for instance, with hurricanes. And there are always folks who will disregard hurricane warnings no matter how severe they are. So did you have to talk over, amongst you and your colleagues, talk over how much alarm you wanted to raise when addressing the public about this this weather event?
MATTAROCHIA: Yes, we do a lot of social science research as far as how certain messages received, what way do we send messages, as far as using percentages or numbers or colors, instead of just a lot of long text or a long speech. So there's a lot that goes into finding what people understand and what they take action upon. As far as my messaging, it was largely shaped by those who have an abundance of experience here, although I have worked in areas where there is a tropical storm or hurricane threat. I would say that the philosophy and the psychology behind creating the message is very similar.
KLEIN: Yeah, so you've been a meteorologist there in Florida, and other parts of the East Coast, and the Appalachian Mountains. How does being a meteorologist compare there to here? Are those regions or any other regions in the U.S. subject to such extreme swings like we have here in Central California?
MATTAROCHIA: Well, that's a very interesting question. And I'm so glad you asked that, because that is something indeed that I have found here in California, that it is more an area of extremes than it is normal. There doesn't seem to really be a normal here. Either it's very dry or very wet. Also, what makes this area very interesting is the quick change in elevation. Right now I'm sitting at 200 feet above sea level. We are responsible for Mount Whitney, so we go all the way up to 14,000 feet. We're also responsible for Yosemite National Park. I can get in the car and drive three or four hours and be at 12,000 feet. There is nothing that compares to that anywhere else in the country or anywhere else that I have been, especially on the east coast. Of course in Virginia and West Virginia we have the Appalachian Mountains and they only go up the 4,000 feet. Those are virtually small hills compared to the Sierra Nevada. So this is much more of an interesting area.
KLEIN: Hmm. That is really interesting. So if we look forward, last winter we saw this historic snowpack, and there is still snow in some places that usually don't see any in July. So what could this mean for this upcoming winter, especially given that it's looking like it could be an El Niño year?
MATTAROCHIA: There are definitely some areas that could hold on to snow at the highest elevations through the summer. I just went skiing a couple weeks ago, which doesn't happen very often in July. Let me tell you, I was excited to do so. But not all of the snow may melt and we don't know what effects there will be on the whole water management system after this summer. So that will have a lot to do with how our next season turns out. We were really lucky that we didn't have any heat waves very early in the summer because it helped the snowmelt be very slow and to a point where our great water managers could put the water in different places. So a lot of people weren't affected that could have been. As far as El Niño is concerned, it is very difficult to give the seasonal forecast. There is a 90% probability that we will have an El Niño this winter. But that is only one of the first indicators that we use to try to determine what a season may be. But it's not something that we hang our hat on. It's important to say that we had an El Niño in 2017, a strong El Niño, and not all of California was wet. This past season we had a La Niña, which is usually supposed to equate to a dry winter, and look what happened. We had probably one of the top three wettest winter seasons on record. So we can't say for sure just based upon that that it is going to be a wet winter, but it can at least get the gears turning and get us thinking about, “okay, how can we prepare if we do have another wet season after this previous winter?”
KLEIN: And then if we look even more forward into the future, what's your understanding of how our region will be balancing extreme precipitation like this with extreme drought? Do you anticipate us going another 50 years before having another winter as wet as this one?
MATTAROCHIA: Well, I cannot say that for sure but there is an abundant amount of research that shows that these extreme seasons are going to become more frequent. So we need to practice for the worst case scenario more often, whether it be extreme drought or extreme above normal. It is something that we are practicing for with our emergency managers and our partners to make sure that we are using unified messaging that all of the agencies understand and that the public understands.
KLEIN: With all that in mind, what do you think are some of the most important lessons to be learned from this past winter?
MATTAROCHIA: I think this only reinforced how quickly California can go from drought to deluge. It was also a phrase that was used to describe the winter of 69. All of us know how extreme weather can be in KLEIN: California, but I think this wakes us up that, just because we have very inactive winters, very dry winters, that we should not rest on our laurels and we should always be prepared for the worst case scenario. Another thing that we learned is that, although we do give a seasonal forecast, we have to include all the possible scenarios and their different likelihoods in that forecast, because a scenario which is not the most likely can occur. And, going into this season, La Niña was forecast and there were some other signals that told us that this would be a dry winter. So we have learned that we cannot pick winners or losers among the computer guidance or the certain indicators like El Niño and La Niña to give people a heads up on what to expect for the wet season.
Kris Mattarochia is the Science and Operations Officer with the National Weather Service in Hanford. Kris, thank you, it's been a pleasure speaking with you.
MATTAROCHIA: Pleasure too, Kerry. Thank you.
