How Much Snow Is on Mount Everest? New Research Insights

Mount Everest, the highest peak on Earth, is covered in snow and ice year-round. However, determining the actual amount of snow at any given time is challenging due to extreme weather and logistical difficulties. Understanding snow depth is crucial for assessing climate change, predicting avalanches, and ensuring mountaineering safety.

Recent research has provided new insights into snow accumulation and its variations across different elevations.

Conditions That Contribute To Snow Accumulation

Snow accumulation on Everest results from atmospheric dynamics, seasonal variability, and topography. The mountain’s elevation exposes it to the jet stream, which carries moisture-laden air from the Indian subcontinent. During the June–September monsoon season, these currents deposit significant snowfall, building the mountain’s snowpack. In contrast, winter months bring drier conditions, with snowfall primarily from westerly disturbances originating in Central Asia. The balance between these patterns dictates Everest’s snow coverage.

The altitude-dependent temperature gradient also affects snow accumulation. Above 8,000 meters, temperatures drop below -30°C, limiting sublimation and preserving snow deposits. At lower elevations, fluctuating temperatures cause melting and refreezing, forming ice layers that alter snow density and stability. Strong winds, often exceeding 160 km/h, redistribute snow, scouring exposed areas while depositing deep drifts in sheltered zones.

The mountain’s steep slopes and orientation further influence snow retention. South-facing slopes receive more sunlight, accelerating sublimation, while north-facing aspects remain in shadow longer, preserving snow. Glaciers, such as the Khumbu Glacier, provide a base for snowfall, while crevasses and seracs disrupt uniform deposition.

Variations In Snow Layers At Different Altitudes

Snow composition and structure shift with elevation due to temperature fluctuations, wind, and moisture availability. Below 6,000 meters, frequent melting and refreezing form dense, granular ice layers known as firn. This transitional state between snow and glacial ice results from liquid water percolating through the snowpack and refreezing, creating a hardened structure that can persist for years.

Above 7,000 meters, the snowpack becomes more stratified, with alternating layers of fresh snow, wind-packed slabs, and ice lenses. Reduced atmospheric pressure and lower temperatures limit melting but enhance sublimation, causing wind to dominate snow distribution. Exposed ridges remain barren, while leeward slopes accumulate compacted snow. This redistribution affects snowpack stability, increasing avalanche risks in certain areas.

Above 8,000 meters, the “death zone” features extreme cold preserving older snow deposits and fostering surface hoar—delicate ice crystals that form under clear, calm conditions. These fragile layers, when buried by snowfall, create weak points in the snowpack. Reduced oxygen and intense solar radiation alter the crystalline structure of older layers, leading to a thinner but highly compacted snow cover, with exposed ice often dominating the terrain.

Techniques For Measuring Snow Depth

Measuring Everest’s snow depth is challenging, but technological advancements have improved accuracy. Traditional methods, such as manual probing with avalanche poles, are impractical due to the mountain’s conditions. Instead, ground-penetrating radar (GPR) has become a primary tool. Mounted on skis, drones, or carried by climbers, GPR emits electromagnetic waves that penetrate the snowpack, reflecting off the underlying ice or rock to determine snow thickness.

Remote sensing technologies further enhance monitoring without requiring human presence. NASA’s ICESat-2 uses laser altimetry to measure snow depth by tracking surface elevation changes. Synthetic aperture radar (SAR), from satellites like Sentinel-1, analyzes radar reflectivity to detect snow distribution variations. Aerial surveys with LiDAR-equipped drones provide high-resolution topographic data, mapping snow accumulation with centimeter-level precision.

In situ measurements remain essential for validating remote sensing data. The 2019 National Geographic and Rolex Perpetual Planet Everest Expedition installed weather stations at various elevations, including one at 8,430 meters—one of the highest ever placed. These stations record temperature, wind speed, and precipitation, refining snow deposition models. Ice cores extracted from high-altitude glaciers provide historical snowfall records, revealing patterns that extend back centuries. By analyzing isotopic compositions, scientists can compare modern snow accumulation with historical norms.

Observed Distribution Across The Mountain

Snow accumulation on Everest is highly variable. Upper slopes, particularly along the Southeast Ridge and North Col, experience significant differences due to wind, solar radiation, and underlying ice formations. Snow depth is greater in sheltered areas, where wind-driven deposits form deep drifts, while exposed ridges and crests are frequently scoured, leaving thin, compacted snow layers or bare ice.

The summit experiences some of the most extreme conditions, with snow accumulation fluctuating based on seasonal weather. Winds exceeding 160 km/h strip away loose snow, exposing ice and rock. Heavy snowfall from monsoon-driven storms can temporarily increase snow cover, but relentless winds quickly erode it. This results in a dynamic surface where snow depth changes dramatically within days, complicating long-term assessments.