Not a whole lot of snow in January, but I know we’re all dancing lots and praying to the snow gods for a solid February and March. To get out in front of the inevitable powder (cue hopeful glances up at the sky), we turned to those who call some of the shots around the region — ski resorts on measuring how much their slopes got; the school district on what goes into deciding when in-person classes are canceled (for weather, not Covid-19); and the mighty Caltrans itself, on how much snow is too much for travel on Interstate 80.
~ AH
Snow inflation?
People often say snow reports coming from resorts are inflated. How do you determine where to measure?
We have two official snow measuring sites at Sugar Bowl Resort: one in the village base area and the other on the upper mountain, between the Christmas Tree and Mt. Lincoln Express chairlifts. We have been recording snowfall at these two locations for several decades. Snowfall measuring sites should be in wide open, wind-sheltered areas. Imagine a calm meadow. That’s ideal. Unfortunately, such locations don’t really exist at our high elevation!
Occasionally, when it’s very windy, all the snow will blow off our measuring boards and we will estimate the new snow total based on what we observe around the resort. Aside from sticking a ruler into the new snow on the railing of our office deck, we don’t use specific measuring tools in those instances. Instead, we rely on reports from groomers, who can give a good approximation of the amount of new snow depth they’re pushing around, and patrollers, who assess and report new snow depths while performing their avalanche mitigation work around the mountain. These types of days are quite rare; on the vast majority of days, we can report exactly what falls on the measuring boards in our twice-daily updates.
~ Drew Jackson, marketing and communications manager at Sugar Bowl | Royal Gorge
Palisades Tahoe collects snowfall data in specific locations and uses redundant methods of measuring to ensure our snow report is accurate. The location where snowfall data is collected needs to be safely accessed by staff, sheltered from wind, away from avalanche paths, and have access to power and WiFi. We want the snow to fall straight down and avoid wind drifting or wind stripping. Locations are carefully chosen; the best option is often an area with medium density trees. We measure at 8,000 feet (Palisades), 7,000 feet (Alpine), and base areas daily at 5 a.m. and 5 p.m. Measurements are done by avalanche forecasters on patrol and grooming staff.
We measure snow manually and remotely. The first way we measure snowfall is by looking at snow stakes; flat boards with vertical measuring sticks attached. With each storm, we measure 12-hour total, 24-hour total, and storm total. The 12-hour snow stake gets cleaned every 12 hours. The storm total stake won’t get cleaned until after the storm is done — this also measures how much the snow settles, an important tool in avalanche forecasting. Adding up all of the 12-hour storm totals gives us the overall storm total, which doesn’t take into account how much the snow has settled.
Instrumentation is also used at our sites. Snow, temperature, and wind sensors as well as precipitation gauges are all used to collect data. Snow sensors measure 12-hour snowfall and total depth, or the amount of snow on the ground. The precipitation gauge measures the water equivalent in the snow and helps determine snowfall rates and density of the snow. Using these redundant methods of measurement ensures our snow reporting is accurate.
For over 40 years we have been taking data and monitoring these snow study sites. Historical and recent data supports our avalanche forecasting program and helps our mountain operations team make decisions every day.
~ Will Paden, Palisades Tahoe ski patrol director
School’s out
How does the Tahoe Truckee Unified School District decide to call a snow day?
It’s all about safety! TTUSD has an extensive evaluation process that goes on behind the scenes at the district any time a winter storm is forecasted.
We look at the forecast for predicted snow amounts and elevation, as well as wind, ice, temperatures, and rain. Our district covers 723 square miles, and we watch the road conditions on Interstate 80, State Route 28, SR 89, and SR 267 (the district’s main roadways and bus routes). We check on secondary roadways as well. We also check on the condition of roadways for students to stand while waiting at bus stops.
We always put safety first, for students and staff. During a storm, we also consult our amazing partners such as the California Highway Patrol, Caltrans, and the National Weather Service offices in Sacramento and Reno to see if it is safe to have school. We also consult the Town of Truckee and the Placer County road department to determine if the roads are safe for buses to travel.
~ Kelli Twomey, TTUSD communications; Nanette Rondeau, TTUSD director of transportation
Shut it Down
What goes into deciding to close I-80?
As an essential segment of the federal freight highway system, Interstate 80 in the Sierra winds through steep mountain passes with towering pines and lakeside vistas. It’s used to shepherd commercial goods throughout the state and beyond and provides a link to world-class ski resorts and mountain communities that rely heavily on tourism.
As the steward of the state highway system in this region, Caltrans District 3 makes every effort to keep this major interstate open during inclement weather and any decision to temporarily close I-80 is not taken lightly. Caltrans and the California Highway Patrol are constantly assessing highway conditions through patrols with safety for all motorists the top consideration.
Factors that contribute to a major highway closure are varied, but during winter there are some very common offenders.
Major-injury or multi-vehicle collisions can close I-80 for hours at a time while emergency personnel provide assistance to motorists and maintenance crews work with tow companies to clear commercial trucks or passenger vehicles from roadways. Speed is the primary contributing factor to collisions during winter, with motorists driving too fast for roadway conditions. When chain controls are in effect, the I-80 speed limit is reduced to 30 mph.
Heavy snow and high winds may also contribute to whiteout conditions in which visibility is severely reduced or non-existent for motorists. This is common on I-80 at Donner Summit where wind gusts can be excessive and create unsafe driving conditions.
Downed trees or power lines have also contributed during the most recent December storms to extended highway closures. For the safety of the traveling public, this debris must be removed from highway lanes before travel may resume.
Caltrans maintenance crews work 24/7 during winter storms to tackle the numerous elements Mother Nature delivers to the state highway system. Before traveling to mountain areas, motorists should be aware of weather conditions and plan ahead for delays and other unexpected events. The free Caltrans QuickMap app (quickmap.dot.ca.gov) provides current roadway conditions and should always be consulted prior to winter travel.
~ Raquel Borrayo, Caltrans District 3 public information officer
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