In Park City, Utah, skiers encountered patches of grass on the slopes for much of the winter, signaling a season that was largely absent. Following one of the warmest winters on record, much of the Western U.S. is now entering spring with historically low snowpack levels and an early heatwave that has pushed temperatures into triple digits.
These challenges might seem like the plot of a climate fiction novel, yet the West’s troubling winter was a harsh reality. Experts warn that the combination of low snowpack and an intense heatwave could lead to a summer prone to climate disasters. “There is no analog,” said Marianne Cowherd, a climate scientist at Montana State University. “There isn’t a year in the historical record we can look to for information … This limits our ability to look to the past for insight.”
A major source of uncertainty is the snowpack, a crucial component of the region’s water system. Snow contributes 60 to 70 percent of the Northwest’s water supply and is vital for the Colorado River Basin, which serves seven states. Yet, the region has experienced its warmest winter on record, resulting in more rain than snow and faster melting of the snow that did fall. The snowpack is critically low, according to the federal Colorado River Basin Forecasting Center, which uses the federal government’s Snow Telemetry network that dates back half a century.
“The majority of them have record low or near record low snowpack conditions,” said hydrologist Cody Moser at the center’s monthly briefing in early March. At that time, he reported that the upper Colorado River basin, which includes the watershed north of Lake Powell on the Colorado-Arizona border, had about 40 percent of its normal snow cover. This has since decreased to 25 to 30 percent.
While overall winter precipitation was relatively average, how that water fell matters. Snow acts as a natural water-storage system, releasing water gradually as it melts, thereby sustaining rivers and reservoirs. Without snow, the moisture quickly evaporates or flows out to the ocean, making it inaccessible. “Even when we’re getting precipitation we’re not storing it,” Cowherd remarked. “A lot of it actually just ends up evaporating or flowing out to the ocean, so it’s not necessarily in a place where we can still access it.”
Cowherd is closely monitoring the snowmelt. Warmer temperatures are causing snow to liquefy faster, but the sun’s current lower solar angle could slow down this melting trend. “I’m really interested to see how those balance,” she noted, emphasizing its importance for the region’s water supply. “We don’t have the reservoir capacity behind human-built dams to hold the amount of water that we need.”
In addition to snowpack issues, a mid-March heatwave has further impacted the West. A heat dome raised temperatures up to 35 degrees above normal, according to Climate Central. Over 1,500 daily records were set across 11 states, with several cities experiencing temperatures above 100 degrees Fahrenheit. The U.S. recorded a national March high of 112 degrees in four cities.
An analysis by the World Weather Attribution Initiative concluded that such a heatwave would have been “virtually impossible” without climate change. “The role of climate change is clear,” Clair Barnes, a researcher at the Imperial College London’s Centre for Environmental Policy, stated. She added that extreme early-year temperatures “tend to be more dangerous for people because your body is not yet acclimatized.”
Although the heat subsided in many areas after about a week, its effects could persist through the summer. Summer-like temperatures and declining snowpack jeopardize the West’s vulnerable water supply. The U.S. Bureau of Reclamation’s forecast indicates that Lake Powell’s levels could fall below the minimum needed for power generation by August, with a high probability by December. Some Colorado residents are already experiencing unprecedented water use restrictions.
“This winter was unusually warm and did not deliver the snow we need,” stated Alan Salazar, CEO of Denver Water, the state’s largest water utility, in a statement last week. The utility declared a Stage 1 emergency, calling for a 20 percent reduction in usage and mandatory restrictions on outdoor watering. “This drought is also a reminder of the impacts of climate change on our water supply,” he said.
Such conditions increase the risk of wildfires. Excessive runoff and high temperatures encourage early vegetation growth that can fuel fires, and unseasonably warm weather turns this greenery into kindling. “Record heat over the previous weeks has put us into early ‘green up’ for the year,” August Isernhagen, a division chief in the Truckee Meadows Fire Protection District, told the University of Nevada, Reno. “This, coupled with many other human impacts on the landscape, has created potential for unprecedented conditions this fire season.”
If these risk trajectories continue, the consequences could be severe. Low water availability might disrupt agricultural operations that supply food nationwide. Wildfires could threaten lives, displace thousands, and cause extensive damage. However, changes could still occur in the coming months.
Barnes noted that an early heatwave doesn’t guarantee more later in the year. The weather between heat events is also significant and could vary. A looming El Nino climate pattern could potentially ease a drought. The snowpack issue might also see improvement.
“We could have a huge snow storm tomorrow and it would be great,” said Cowherd. But considering current weather forecasts, she cautioned, “I don’t think this is likely to happen.”
