ADRIAN FLORIDO, HOST:

There aren't a lot of people who would feel overcome by joy at having 17 feet of snow dumped on top of them. But there are some, and one of those people is Andrew Schwartz. He's the station manager for the University of California Berkeley's Central Sierra Snow Laboratory, which measures snowfall from its perch up in the Sierra Nevada mountains east of Sacramento. Seventeen feet is what Schwartz has measured in just the last month, a record. And so we called him up to ask what this means for the severe drought California has been experiencing. Andrew Schwartz, welcome.

ANDREW SCHWARTZ: Thank you so much for having me on.

FLORIDO: Seventeen feet in just the month of December - that sounds like a ton of snow. But how does that compare exactly?

SCHWARTZ: Yeah. You know, this - it is definitely a ton of snow. And we actually wound up with about 214 inches total for the month of December, which is nearly 18 feet. And that is now our snowiest December on record. We had had the previous December back in 1970 as the snowiest on record with 179 inches. So we definitely blew that record out of the water, to say the least. And it's terrific considering that, you know, roughly a week to a week and a half into December, we still had bare soil, bare ground up here.

FLORIDO: Officials have determined that the snowpack is at about 160% of the average for this time of year. Is that right? That sounds like good news for reservoirs.

SCHWARTZ: It's very good news, where we are right now, you know, the important bit being that ultimately, while we have this incredible snowpack, we do need the additional water resources on top of it. If we get, you know, a long string of dry, warm months, then it's not really going to help us out as much as we would like it to if we had future months that were, of course, a little bit more wet and cooler. We definitely want the snowpack to hang around as much as possible and for more of it to accrue. The drought that we're - that we've been in out here has been so severe that we really need as much snow as we can get. There's not really a limit on how much we want. But this is an absolutely terrific start to the season, for sure.

FLORIDO: Why is it important for the snowpack to stick around for a while, as you said, as opposed to just melt and filter down into the reservoirs?

SCHWARTZ: Well, for one, fire dangers is really, really reduced by having our snowpack stick around up here. On deep snowpack years, it might hang out until July or August and keep the soil wet, keep the forests moist and, you know, really help us out with our fire danger, which has led to so many catastrophic fires over the last several years. So that's one thing.

The other thing, too, is we really want as much of this to stay on top of the soil and trickle in slowly as possible. Our dry months are always going to be during the summer and the early autumn. And so as a result, what happens is, when that soil dries out, any type of precipitation event that we get after that realistically goes to making that topsoil wet again rather than running off into reservoirs. So if we can keep the snowpack doing that for a little bit longer, then any additional rain or snow that we do get will go towards running off into reservoirs rather than replenishing the moisture that has evaporated from the soil.

FLORIDO: Well, last summer was the driest since we started keeping records here in California 126 years ago. What does it say to you that in the course of half a year, we had the driest July on record and the snowiest December on record?

SCHWARTZ: These whiplash weather events that we're seeing are definitely signs of climate change. And we've seen other signs of climate change here on the summit as well, including increases in our maximum and minimum daily temperatures, as well as a shift away from snowfall as a whole during the winter and more towards rain.

And, you know, it's not just year to year. We had the second snowiest October on record this year. And then in November, when we only got five inches of snow, that was one of the lowest ever - and right back into December, where we had the snowiest December on record. So it's a lot of interannual variability from year to year, but there's even some of that to month to month at this point. So it's really just another case of climate change making the extremes more extreme.

FLORIDO: So what are you keeping an eye out, Andrew, as the winter progresses? What does the rest of the season look like for you? And when will you know whether things are looking up or down in terms of your goals for this season?

SCHWARTZ: Some of the more, I guess, medium- to long-term forecasting products have shown that we might be drying out and warming up a little bit here over January. And that's definitely something that we were expecting as a whole with this winter, is being a little bit warmer and drier. And that definitely happened in November. And, of course, the opposite happened here in December. So we're kind of seeing a mixture of, you know, again, those swings, going back to a drier January and hoping that's not necessarily going to happen.

But, you know, there's a lot of statistics thrown around with it being a La Nina year. And this area and in general could really go either way during a La Nina year. We don't have a wet pattern or dry pattern that can be attributed to it. But with that being said, we do tend to be drier in these La Nina years. So even though December was a record-breaking month, it's quite possible that the upcoming months are going to be drier. And we're hoping that's not the case, but it's looking like it will be for the time being.

FLORIDO: That was Andrew Schwartz. He's UC Berkeley's Snow Lab station manager. Andrew, thank you for being with us. Happy New Year, and stay warm.

SCHWARTZ: Happy New Year. Thank you so much for having me on. Transcript provided by NPR, Copyright NPR.