With winter weather on the way, NHPR's Chris Martin sat down to talk to meteorologist Tony Vazzano, who specializes in mountain weather and snow. His company, North Winds Weather, provides specialized weather reports to ski areas across northern New England.
Chris: This is Something Wild. I’m Chris Martin from New Hampshire Audubon. While it’s still hard to know in advance what the coming winter has in store for us, here in NH we’ve got someone who keeps a close eye on every snowstorm headed our way. Tony Vazzano is a meteorologist and the owner of North Winds Weather. He’s an expert on mountain weather, and advises ski areas across northern New England with customized forecasts. He joins us from his studio in Center Sandwich. Hi Tony, thanks for joining us!
Tony: It's good to be here Chris, thank you.
C: So what’s the most challenging part of forecasting snow and winter weather in New England?
T: I suppose the most challenging part is to be accurate in so many different localities. Most of us, whether you’re a TV meteorologist or doing what I do with ski areas across Northern New England, you have to come up with the snow amounts for a whole different area every time. So to be accurate in 20 different places for every storm... that's difficult.
C: Help us understand exactly how snow forms.
T: Snow forms way up high in the atmosphere, in fact much of the rain we see begins as snow in the clouds. And there’s nuclei up there, the upward motion, the moisture has to be just right… once the moisture builds around the nuclei it becomes heavy enough to move downward.
C: Yeah, I think we talked on a previous Something Wild about the fact that snow actually even forms in the middle of summer in thunderstorms, is that correct?
C: Tell us more about the water content of snow and how much snow can we get from an inch of rain?
T: Well it’s quite variable depending on the atmospheric conditions at the time. I’ll say in general, anywhere from 7 to 25 inches from one inch of water. And it doesn’t always relate to the temperature on the ground, it often relates to the temperature in the layers of air above the ground during the first several thousand feet as you go up. So that makes it quite complex to know just how much snow is going to fall from an inch of water.
C: So you’re saying it’s somewhat tough to predict whether an approaching storm is going to drop wet, heavy snow or light fluffy snow?
T: That’s a little more simplified, let me give an example of last winter when we had a situation here when it snowed one day the high temperature was in the single digits. One would expect a more fluffy snow. Because when the snow came, it apparently formed in low levels of the atmosphere, much like drizzle with those small rain droplets as opposed to big rain droplets. Well these little tiny snowflakes packed together very tightly, especially with some wind as they fell. So instead of a 10 to 1 ratio or really a 20 or 30 to 1 ratio you might expect at that temperature, it was less than the 10 to 1. I think 3 tenths of an inch of moisture only gave us two inches of snow instead of 6 or 7 or 8.
C: There’s a lot of uncertainty in it.
C: I want to talk about geography for a second: I’ve heard the term snow shadow used in a lot of different contexts when talking about mountain snowstorms. Do we see any kind of snow shadow effect in our state based on elevation and terrain?
T: Almost every time it snows.
T: It doesn’t take too much elevation to affect the amount of precipitation. It’s also known as a rain shadow in the summer. But in the winter, in a winter storm we call it a snow shadow. Where I live in Sandwich, for example, big storms are unusual because of the Sandwich range and the White Mountains, you know, these mountains go up to about 4000 feet and when the wind is Northeast and North during the storm, it’s coming from that direction into where we live. And so during a big northeaster while some, maybe the western highlands of the state could see 25 inches, we might have 12 inches and in fact in over 30 years here in Sandwich I’ve only seen more than 20 inches once in my section of town because of that shadow.
C: Okay, I can verify that because I live over in the Kearsarge area and about every other year we get about a 30 inch snowstorm.
T: There ya go. And even in eastern parts of sandwich where that influence of the White Mountains is not as direct, 20 inch storms are not that unusual there. So it doesn’t take much distance for things to change dramatically.
C: What’s going on, the wind flow is lifting the moisture up and it’s falling out before it gets to you?
T: Well that’s part of it. Rising motion does, as we just spoke, create precipitation, so as the wind’s coming up one side of the mountain, it is ringing out some of the moisture. By the same token, a downward motion in the atmosphere is physically a drying motion. And so that’s very evident in certain storm situations in certain places. One of the most interesting to me is the Ossipee mountains nearby here because it’s a perfect circle. And now with the internet and all these reports we get so many reports that you can actually see how this shadow works around the mountains depending on what type of storm is coming through. And it’s quite fascinating. One side of the range could have an inch of rainfall while another side could have 3 and a half inches - just 8 miles away.
C: I think it’s really fascinating that you work closely with the ski areas in the state which everyone knows they’re an important part of our winter economy. What sort of information do you provide for them and how far in advance can you tell them what’s coming?
T: Well I provide them with pretty much as much weather information as you can imagine they’re going to need. It’s a weather forecast but there’s a lot of detail in it. One example might be for when I give them the forecast in the morning for the next 30 hours, for every 3 hours I’m giving them the temperature, the wind the humidity on top of the mountain, the middle of the mountain, the bottom of the mountain so they can look at that and know where and when to make snow and also it affects their grooming operations heavily.
C: And these are, for them, economic decisions, aren’t they?
T: Absolutely. In fact, I don’t know if it works this way in NH, but in VT where many of my clients are, the rate they pay of electricity changes during the day, depending on different times of day, different times of week. And so they actually try to match up sometimes when they can make the most snow at the coldest temperatures at the cheapest power rate.
C: It almost sounds like the stock market.
C: Well that’s fascinating, I didn’t realize how detailed and complicated… but it’s up to them to make the decisions about it - you’re providing them with the data and they’re the ones calling the shots on it, right?
T: That’s correct because, as you mentioned earlier, it’s an economic decision. And if they really need snow badly, they might do it at 30 degrees if the humidity’s only 60%. But under most conditions, to save money, they prefer to wait for the temperature to be 27 and the humidity to be a little less.
C: So, you’ve been forecasting NE mountain weather for, what, 40 years?
C: Wow, what in all that time - four decades - what changes have you seen in technology, you know, the tools of your trade, and, for that matter, what changes have you seen in the weather itself?
T: Well obviously the change in technology has been tremendous, especially in the past 20 or so years. Back when I started we used to work off the old teletype system. We had a thermal facsimile machine, which is kind of a large, I don’t know, three foot thing. We’d use rolls of moist paper going through the machine to print weather charts every morning. I used to come in and cut up about 20 feet worth and then look at the teletype reports. And there was never, ever enough information. Now, there’s literally too much information to look at. I could look at information all day to make the forecast better and never have time to issue a forecast. I have to draw the line.
C: And what about the weather itself? I mean, 40 years is a good deal of time to draw on. Have you seen anything that jumps out to you as changes that we’ve got now versus 40 years ago?
T: Certainly, in that kind of time you’re going to get some climate flux no matter what. But we have seen, I think, some more dramatic changes of late in the past few decades. I know when I first moved to Sandwich about 35 years ago, the incidence of 2 inch rainstorms was very rare. To get 2 inches of rain within a 48 hour period… you know in might happen a couple of times in a year, but you also went sometimes a couple of years without it happening. It was a pretty rare event. The rainstorm that just came through here was the fifth one we’ve had this year here and in the past decade or so, that’s not unusual. So, the incidence of these 2 inch rain evens has increased, I don't know exactly, it was difficult to look over the old data and always determine a 48 hour period for some of these rain events based on the data I was using from my neighbor. But it appears to have increased maybe 4 or 5 fold, which is just a tremendous difference. And that's why in the past decade you've heard about these so-called hundred year floods happening every five and ten years all of a sudden.
C: Tony, I've enjoyed talking to you so much today, I want to thank you for joining us.
T: Thank you Chris.
C: Tony Vazzano is a meteorologist and the owner of North Winds Weather. I'm Chris Martin. Something Wild is a joint production of New Hampshire Audubon, the Society for the Protection of New Hampshire Forests, and NHPR.