Mountain Rain or Snow program lets you help forecasters

ELKO — As weather in Elko becomes more stormy, a simple program allows people to participate in scientific studies tracking precipitation, with just the push of a button on a smartphone app.

"Mountain Rain or Snow involves sending real-time observations of winter precipitation — rain, snow and mixed precipitation — to scientists," Desert Research Institute scientist Meghan Collins said.

The project launched in 2020 and has collected over 65,000 individual pieces of data so far. The winter of late 2023 and early 2024 resulted in 25,000 of them.

"A lot of our local residents might have had the experience of coming down to Elko, where it's drizzling, and then driving up over Lamoille Summit. At some point, you drive through a transition from rain to snow. It can be hard for forecasters to predict the elevation where that rain-snow line will happen," Collins explained.

"Community observers in our region, who send observations of rain and snow through the web app, are helping to put our region on the map and ultimately, over the long term, improve forecasts and also our understanding of hydrology," she said.

"The big emphasis this year is that our observations are being shared in real time with meteorologists across the West to help them update and refine the forecasts that they use from the national blend of models," she said. "Our team has created what we call a real-time precipitation phase map, which is another way of saying that observations submitted by community observers are able to be seen by weather forecasters instantaneously.

"Those forecasters can use those real-time observations to validate or ground-truth their modeled weather predictions. This matters because in the West, especially in arid mountainous regions, it can be very hard to predict the line where rain transitions to snow."

She said anyone who texts the word GreatBasin to their project number and signs up can then just "look out the window and anytime that it's snowing, they can send a snow observation or anytime it's raining, they can send a rain observation."

"And if you're located in one place, let's say you're sending an observation from your place of work, we would be able to see if you're making submissions at regular intervals. We would be able to see the transition in a storm event between, say, rain or snow or snow to rain," Collins explained.

"Likewise, if somebody were sending observations from the passenger seat of a vehicle, it would essentially form a line," she said. "Imagine if someone was driving down Mountain City Highway and the passenger in their car was logging a precipitation phase observation every 2 miles. We would see a little transect or a trail of observations. Maybe they would be rain, rain, rain, followed by snow as they go over Adobe Summit. And then after they come down from Adobe Summit, it might be rain again. So using those kinds of contributions from people across the region, we can track the rain and snow level in real time."

She said NASA uses a series of satellites that track weather.

"They're part of NASA's earth science mission. Those satellites use remote sensing to estimate precipitation phases, rain vs. snow. Those satellites collect observations and they have an algorithm that makes an estimate — this is the probability of snow, this is the probability of rain," Collins said.

"The challenge with that is, if you're assuming that it's always raining above 32 F," she noted, "you're kind of missing some of the nuance that happens right around the freezing point."

"Most of us here in the high desert have experienced a time when you might have looked out the window, say you were driving in your car, and you noticed snow falling at 34 F or 35 F. This is not a change to the law of physics," Collins explained. "Sometimes, snow just takes longer to melt as it falls from the colder layers of the atmosphere. And that's the point where satellites struggle. So, our work is contributing to the understanding of that transition between rain to snow. Those temperature thresholds can happen at different temperatures across different regions and across different storms, to provide better nuance for the algorithms that drive the estimates behind those satellite observations of weather."

She shared some of the other outcomes of collecting weather data.

"On a small-scale level, we have a stronger network of National Weather Service forecasters in Reno and Salt Lake City and Sacramento who are using the information to validate their forecast," Collins said. Also, "people who work on avalanche forecasting, including meteorologists and specialists in avalanche prediction, have been doing case studies to understand how Mountain Rain or Snow observations can help with avalanche forecasts. This is led by my colleague, Anne Heggli. She found that the Mountain Rain or Snow data set can help forecasters understand and predict critical changes in the snow pack which can impact avalanche forecasting and ultimately, safety."

Collins said Heggli found "there were really informative things that could come out of this process, like understanding where particular layers in the snow pack might have been unstable as a result of where when it might have rained vs. when it might have snowed."

For instance, "floods in our region can happen when a warm storm brings rain and falls on a heavy snow pack. In the past two winters, there were some concerns about heavy rains melting the dense snow pack in the Rubies, and it didn't happen," she said.

"At the end of the winter season in 2022, there was a really large snowpack in Yellowstone National Park and there was a big rain event that happened," she said. "The rain melted the snow in the mountains and it caused a lot of damage down the valley. That Yellowstone example is a time when the meteorological forecasts were predicting snow at certain elevations, when in fact, they got rain. And so the communities weren't as prepared as they might have been, had that snow level forecast been a little bit more active. So this is an example of how improving the understanding of rain-snow lines over time can contribute to preparedness."

She said it's easy to help.

"If people want to help put our region on the map and help advance the science behind these problems, they can text GreatBasin to 855-909-0798 and that will get them signed up for weather alerts. So, when there's a storm of interest entering our region, they'll get a little text message that says snow is on the way," she said.

"We received over 32,000 observations last winter alone. It was an incredible year, demonstrating just how committed our observers are. From coast to coast, there were 600 people involved. One of the top 10 observers is right here in the Great Basin, right here in Elko," Collins said. "Together, those people are making a huge contribution to the science."

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