From its base at the southwest corner of the Seattle campus, the provides expertise, tools and resources on “all things climate” to partners and communities across the state.

was announced in the spring as the . Mauger is a research scientist with the 91̽��Climate Impacts Group, which now houses the state climatologist’s office. Mauger’s research focuses mainly on water and floods in the context of climate change.

, a 91̽��research scientist and the deputy state climatologist, studies such things as nighttime heat in Seattle and new ways to display weather data, as well as other trends involving heat and drought.

Together, they provide data and share news on whatever’s in the skies. From heat domes to hailstorms, from snowpack to summer drought, they provide perspective on the short-term and long-term weather woes and questions facing Washingtonians.

“Our goal is to help people understand the climate and how it affects their daily lives,” Mauger said.

Right now, many people in the region are curious about the upcoming winter season.

“This year we’re expecting to see a weak La Niña develop in the tropical Pacific Ocean,” Bumbaco said. For Washington that means “on average, we tend to have cooler-than-normal temperatures, a little bit more precipitation, and more snowpack by the end of our winter season during La Niña winters.”

Mauger and Bumbaco also conduct research on changes in rainfall patterns and flood risks, and on temperatures and wildfire risks for the coming season and over the longer term. Visit the Office of the Washington State Climatologist’s website to check out the seasonal , a list of or to subscribe to a on the current state of Washington’s climate.

For more information, contact Mauger at mauger@uw.edu or Bumbaco at kbumbaco@uw.edu.

The new is freely available on the Office of the Washington State Climatologist’s website. It replaces a tool made more than a decade ago that collected snow depth data from the NWAC website to create a simple graphic on the state climatologist’s website.

“When that display wasn’t working, that’s the one where we would get emails from ski enthusiasts or other meteorologists or climatologists. To us that was a good sign that we should rebuild it,” said Karin Bumbaco, a 91̽��research scientist who is the assistant state climatologist.

The new version, built with support from Tableau, is interactive, displays more data and is more reliable. It lets users explore differences in mountain snow depth from one season to the next and create a graphic of the results.

“This is a tool that people in the weather community, like meteorologists and climatologists, as well as snow recreationalists, can use to communicate the current snow conditions and how they relate to average conditions and previous years,” Bumbaco said.

A default view shows the current year compared to the past 30 years of data at a single location. Changing the settings can display measurements back as far as 1927 for the longest-running stations, on Mount Baker at Paradise on Mount Rainier. Measurements go back to 1974 for the two most recent stations, at Mount Hood Meadows and Timberline in Oregon.

The Northwest Avalanche Center monitors mountain snow depth for their forecasting operations as avalanches pose risk to roadways and people venturing onto the winter slopes. Data are entered 12 times a year, on the 1st and the 15th of each month, during the monitoring season from Nov. 15 to May 1.

The monitoring sites are part of the center’s mountain weather station network. Some sites are owned by the Washington state Department of Transportation, while others are partnerships between NWAC and the transportation department, ski areas or national parks. While other measures exist, they don’t have the same history of similar measurements.

“We use this tool to track how our snow depth is building across NWAC’s forecast region in a historical context,” said Dennis D’Amico, meteorologist and forecast director at the Northwest Avalanche Center, who worked on the project. “Local professionals and recreationists track this report all season long. This new tool will allow them to explore historical snow depth data in a modern visualization tool at winter recreation access points.”

The new tool complements a previous 91̽��data visualization looking at long-term weather trends. Official trends in mountain snowpack are measured in snow-water equivalent, or the amount of water when the snow is melted. Those trends vary throughout the state and generally show long-term declines of about 3%-10% per decade, Bumbaco said.

“Tableau Public is an ideal medium for this sort of civic, historical data,” said Blair Hutchinson, product manager at Tableau. “The visual dashboards we created provide people with a great way to interact and make informed decisions regarding the snowpack on a seasonal scale.”

The many people seeking outdoor recreation during the pandemic are lucky that as of early February, most of the 11 stations are now measuring slightly above-normal snow depth. This winter had been forecast to be an La Niña year, which is often slightly cooler and wetter in the Northwest, Bumbaco said. It’s delivered on half that promise, with December-January conditions generally warmer and wetter than average.

The continues to predict conditions slightly cooler and wetter than normal, Bumbaco said, which means we’re likely to see a healthy snowpack.

The new visualization tool was supported by Tableau.

For more information, contact Bumbaco at kbumbaco@uw.edu or 206-543-3145 and D’Amico at dennis.damico@nwac.us.

The 91̽��’s College of the Environment has teamed up with Seattle visual analytics company to create a new, interactive visualization for historical observations of temperature and precipitation in Washington, Oregon, Idaho and western Montana, and for Washington snowpack.

The lets anybody interact with the records going back as far as 1881 and look for significant trends.

“This tool lets anyone, from researchers to meteorologists to members of the public, look at the actual data to motivate why we should care about our climate changing, and see how it is changing in our own backyard,” said project lead , the assistant state climatologist for Washington.

The tool uses Tableau’s interactive visual analytics platform to select one or several National Oceanic and Atmospheric Administration stations in the Pacific Northwest, plot the trend and play around with time periods, seasons and other variables.

“You have to have people explore historical climate in order to understand the context of future climate,” said project co-lead , lead scientist for science communication at the Climate Impacts Group. “We hope Tableau visualizations like these will become go-to resources for engagement and exploration of climate data in our region.”

A previous version of the tool ran on Google Maps and was the most popular feature on the state climatologist’s website. But it sometimes crashed and it was cumbersome to load new weather observations, so it was updated infrequently.

The new tool was created in the summer of 2018 when the 91̽�� and hired 91̽��atmospheric sciences alumnus to migrate the tool from Google Maps to Tableau.

The new platform launched in September is more visually appealing, more stable and is easier to update, with plans to update observation records every few months. Users can access it to easily explore the data for their city or region, and produce graphics that display the data and any significant trends.

The tool displays quality-controlled records of temperature and precipitation beginning in the late 1800s. These data are a subset of federal weather observations, known as the , which includes the best-located stations with the longest records the agency recommends using to look at climate trends.

On the map, stations with an increasing temperature trend show up as a red bubble, and decreases are blue. A statistically significant increase gets a big red bubble, while a statistically significant decrease gets a big blue bubble.

For temperature, the map is filled with big, red bubbles.

Are those trends the impacts of climate change in the Pacific Northwest?

“Definitely,” said Bumbaco, who is also a research scientist at the UW’s Joint Institute for the Study of the Atmosphere and Ocean. The most striking trends are in summer nighttime temperatures, the daily minimums, which she says are increasing across the region.

The team surveyed other state climatologists, on-air meteorologists and other potential users in the region to get feedback when creating the tool.

People can use the map’s navigation button to zoom in or out, and then click a triangular button below to access buttons that select regions of the map. Clicking on a single station pops up a summary of its data and creates a line graph below that shows each year’s observations over time. Clicking several stations compares those observations. Tools at the left can have the popup window show changes over the entire period of observations, per year or per decade. Users also can add a trend line to the line graph, add an average value, or compare a location with the statewide average.

The tool gently encourages users to display statistically significant trends by showing a gray color if the time period is shorter than 30 years, considered the minimum for a climate trend.

Along the bottom of the screen are buttons that let users download, export or email their visualizations.

, a technical advisor at Tableau who helped create the tool, said the ongoing collaboration allows him to learn more about how to visualize unique datasets and help people create user-friendly interfaces.

“My basic advice for new users is to interact,” Cory said. “People are used to visualizations being static, and they don’t realize that if I move my mouse over, something happens, and if you click, something happens.”

The tool also includes snow-water equivalent, a measure that takes density into account, for Washington state beginning in 1930 from the federal sites. The snow observations are best for April and show decreases in many parts of the state.

Precipitation in the Pacific Northwest doesn’t show a clear trend, though many areas show wetter springs, Bumbaco said.

The Climate Impacts Group has been working with Tableau since 2016 to create other, more forward-looking , such as a future , or projected changes in around Leavenworth, Washington. The partnership with the Office of the State Climatologist creates consistent and common visualization tool for the two groups.

“Our collaboration with Tableau has helped us to consider everything from what colors you use and how thick should the lines be, to addressing bigger issues, like where you start with a visualization, how users navigate through it, and what information users need to navigate it successfully,” Roop said.

The updated Pacific Northwest climate trends analysis tool is open source, so other regions of the U.S. or other countries could potentially use it to display their historical observations using the same Tableau interface.

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For more information, contact Bumbaco at kbumbaco@uw.edu or 206-543-3145, and Roop at hroop@uw.edu. For Tableau communications, contact Dan Jensen at djensen@tableau.com.

More example visualizations are .

In August 2018, , the assistant state climatologist for Washington and a research scientist at the 91̽��’s , commented on the summer weather across the state.

“It’s definitely an unusual summer. We’ve been drier than our normally dry, and also temperatures have been warmer,” Bumbaco said.

Washington had its third-warmest summer — for the months of May, June, July and August — since 1895. The trend was less the result of heat waves than just a steady, overall warmth.

“While we haven’t had a really extremely hot days, say in the upper 90s in Western Washington, the baseline is so much warmer,” Bumbaco said. “We haven’t seen that many days of cool, cloudy skies that tend to make up a summer in Seattle, in particular.”

A healthy water supply locked in winter snow got derailed by unusual spring and summer weather.

“In the beginning of April, we had normal to above-normal snow throughout Washington state, and that’s really important for our water supply later in the spring and summer,” Bumbaco said. “But beginning in mid-April, temperatures warmed drastically. So that snowpack melted very rapidly — much faster than usual.”

Summer rainfall was only about 20 to 40 percent of normal for much of the state.

That hit some places harder than others, Bumbaco said.

“Places with reservoirs to hold that water, like Yakima, were able to store that and release it slowly,” she said, for use throughout the summer. But other regions of the state, especially those that rely on summer rain, were experiencing drought conditions by the end of August.

The of the monthly newsletter that Bumbaco produces for the , based at the UW, summarizes the conditions across the state and shows how the 2018 season compared to previous summers on record.

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For more information, contact Bumbaco at 206-543-3145 or kbumbaco@uw.edu.

And if you don’t sleep well in hot weather, this might be a good time to buy a fan, since records show that on average heat waves tend to strike around the last week of July.

91̽�� research shows that the region west of the Cascades saw only three nighttime heat waves between 1901 and 1980, but that number quadrupled to 12 nighttime heat waves in the three decades after 1980, according to a published in the July issue of the .

Nighttime heat waves are when the daily low is in the top 1 percent of the temperatures on record – in Seattle above around 61.5 F – for at least three nights in a row.

“In general, minimum daily temperatures have been warming faster than maximum temperatures, so we’re not surprised to see a trend in the minimum events,” said corresponding author Karin Bumbaco, a research scientist at the . “Still, we were surprised to see this significant increase in the frequency of nighttime heat waves.”

She and co-author Nicholas Bond, both with the , began the investigation after fielding questions during the , which broke temperature records and led to a local run on fans and air conditioners. People wanted to know how that event compared with others in the history books.

The two ran the numbers with the help of Oregon State University’s at the Oregon Climate Service. They studied temperature readings west of the Cascade Mountains in Washington and Oregon from 1901 to 2009, looking for instances where the daytime high or nighttime low temperature hit the top 1 percent of readings for at least three consecutive days.

The 2009 scorcher set records in daytime temperature, but it was the string of warm nights that stood out, Bumbaco said. By their definition it was a three-day daytime heat wave in the Pacific Northwest – but included eight consecutive hot nights, the longest seen in the observational record.

“It was hard to cool down at night, there wasn’t much relief at all,” Bumbaco said.

Researchers also found a clue to suggest why we’re seeing more hot nights. It’s well known that Pacific Northwest heat waves occur when breeze off the ocean is replaced with air flow from the east, which warms up as it flows down the western slope of the Cascade Mountains.

But they found another trait for nighttime heat waves. The records show that nighttime heat waves happen during high humidity, where water vapor in the air serves as a blanket to trap heat.

“Forecasters already do a good job at predicting when heat is coming into the region, but this might help differentiate between hot days versus hot nights,” Bumbaco said.

Predictions are that climate change will bring longer, more extreme and more frequent heat waves during the day and night. The paper found no significant trend in the historical record of daytime events.

Though it was not part of the study, the recent late-June 2013 hot spell included just two extremely hot days, but readings at SeaTac Airport showed it qualified as yet another nighttime heat wave, Bumbaco said.

The study also includes a preliminary look at health effects from heat waves, which in the U.S. account for about 1,500 deaths each year. It found a 50 percent increase in the number of regional hospitalizations coded as being related to heat on dates the authors identified as heat waves. The most heat-related hospital admissions were during the 2009 heat wave and during a 2006 event that had the warmest nights on record. This corroborates other studies suggesting that nighttime heat has the most impact on human health.

Northwesterners are unlikely to draw sympathy from people across the country who are weathering triple-digit summer temperatures. But there is reason for concern. Because the region has mild temperatures people are not acclimatized to extreme heat and, perhaps most importantly, most people do not own air conditioners in their homes.

The research was funded by the State of Washington through the state climatologist’s office.

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For more information, contact Bumbaco at kbumbaco@uw.edu or 206-543-3145.