Yosemite National Park Officials Issue Warning on Cold Water Hazards from Snowmelt

Yosemite National Park officials have issued a warning to spring travelers regarding hazards from waterfalls and rivers. The park's waters have become dangerous due to snowmelt from the Sierra Nevada mountains. This alert comes after a drowning incident at Shasta Lake in early April, where a five-year-old boy fell into frigid waters without a life jacket, according to the Shasta County Sheriff’s Office.

The incident at Shasta Lake occurred during a family outing. The Shasta County Sheriff’s Office described it as a reminder of how quickly such outings can become fatal. While temperatures in California are warming, the melting snowpack sends cold runoff into the Merced River and surrounding creeks.

Park officials stated that every stream in Yosemite is currently running fast, high, and cold. Water temperatures are around 40°F (4°C), which can cause cold shock upon immersion. Cold shock triggers the gasp reflex, leading to involuntary inhalation of water and initiating the drowning process.

The California Governor's Office of Emergency Services reported that immersion in water below 77°F affects breathing.

In water between 60°F and 70°F, breathing becomes difficult to control. In water between 50°F and 60°F, muscle control is lost within minutes. Park officials noted that submerging in 40°F water can immediately induce cold shock.

This physiological response poses risks even to those not intending to enter the water. Visitors may encounter hazards while taking photos, playing on rocks, or cooling off near the edges. The granite boulders around waterfalls, even those appearing dry, are slick from mist and spray.

A slip can lead to falls into currents that appear calm but carry strong undertows. These conditions affect hikers, families, and photographers in the park.