El Niño and snow in the Idaho Panhandle

Many people observed the lack of snow at our beloved ski resorts around the Idaho Panhandle this past fall to early winter and asked, “Where is the snow?” Some might suggest it’s the result of El Niño, but what does that mean? This article describes what El Niño is, weather conditions it often produces, and the effects El Niño may have on our snowpack.

El Niño is part of a phenomenon called ENSO — El Niño Southern Oscillation. To describe ENSO, we’ll have to look south towards the equator and west coast of South America. Along the equator, winds blow from the east. This easterly flow between South America and Australia pushes ocean water to the west, towards southeast Asia and northern Australia. When these winds move water away from the west coast of South America, deep, cold ocean water rises to replace the lost mass of water being pushed to the west in a process called upwelling. When those winds are weak, little amounts of ocean water are being pushed to the west, decreasing the amount of cold water upwelling, and increasing sea surface temperatures; this is an El Niño event. When these winds are strong and move larger amounts of water, it increases the amount of upwelling, thus bringing more deep, cold water to the ocean surface and cooling it down. This scenario is called La Niña. When sea surface temperatures are neither above nor below normal, ENSO conditions are considered neutral.

El Niños and La Niñas alter the meteorological conditions over the Pacific Ocean, and subsequently the weather patterns that affect our region. Under El Niño conditions, wetter storm tracks typically progress towards the southern part of the U.S., and generally results in dry and warm conditions in the Northwest. In La Niña, cooler and wetter systems come from the Gulf of Alaska down across the Northwest states but typically leaves the southwestern U.S. dry.

So how does El Niño affect snowpack in the Idaho Panhandle? El Niño’s typically result in low snowpacks in the Panhandle due to fewer cold storms and warmer-than-normal conditions. The warmer air affects the precipitation type. So instead of snow, rain is often present, especially in lower elevations. 2005 and 2015 are El Niño years similar to the current 2023-2024 winter season. Each had near-record to record-low snowpacks for their winter seasons. It’s important to note, that just because it’s an El Niño winter, it doesn’t mean that’s always the case. There are many instances of winters with significant snow events during an El Niño resulting in near to above-normal snowpack. Such years are 1995, 2003, 2007 and 2009.  However, this year we are seeing an even lower snowpack early in the season compared to 2005 and 2015. 

In addition to warmer conditions from El Niño, a long, narrow strip of air carrying abundant moisture from the tropics called an atmospheric river passed through in early December. While the storm brought significant precipitation and pushed snowpack to near-normal conditions, the warm, tropical air rushed into the region and quickly transitioned the snow to rain. These conditions melted up to 10 inches of snow at all elevations monitored in the SNOTEL network (automated snow measurement stations) in the Idaho Panhandle. The atmospheric river event coupled with infrequent storms and dry conditions typical of El Niño has resulted in the lowest snowpack on record for most SNOTEL sites in the Idaho Panhandle as of Jan. 1. Even with the extreme cold and frequent storms throughout January, it was still not enough to pull the Idaho Panhandle basins out of near-record to record-low snowpack. These conditions are considered a snow drought and can cause low water supply and reduced streamflow.

Winter is about halfway over, but there is potential for snowpack conditions to improve, however, the snowpack has a tough road to reach near-normal conditions. ENSO is expected to return to neutral conditions from April through June, so El Niño should hit its peak soon. Only time will tell if weather patterns continue to play out to traditional El Niño conditions, potentially causing a record-low snowpack, or if this winter season will improve.

Guest author Cody Brown is a hydrologist with the U.S. Natural Resources Conservation Service.

The Our Gem Coeur d’Alene Lake Collaborative is a team of committed and passionate professionals working to preserve lake health and protect water quality by promoting community awareness of local water resources through education, outreach and stewardship. Our Gem includes local experts from the University of Idaho — Idaho Water Resources Research Institute, Coeur d’Alene Tribe, Idaho Department of Environmental Quality, the Basin Environmental Improvement Project Commission, Kootenai Environmental Alliance, Coeur d’Alene Regional Chamber of Commerce and Connect Kootenai.