Antarctica's Snowfall: Not What You'd Expect

Antarctica has no meaningful "average monthly snowfall" because it's the world's largest desert—precipitation is extremely low, highly variable, and not evenly distributed.

The Numbers

• Annual precipitation (water equivalent): ~166 mm (6.5 in) average — desert threshold is 250 mm
• Interior plateau (e.g., South Pole): ~50 mm/year — hyperarid
• Coastal areas: 200-600 mm/year — still arid
• Peninsula: Up to 1,000 mm/year — subpolar maritime

Seasonal Pattern

• Winter (Apr-Oct): Most precipitation falls as "diamond dust" (ice crystals) — not classic snowflakes
• Summer (Nov-Mar): Warmer coasts may get rain; interior still frozen
• No monthly average: Highly episodic — storms deposit most annual total in few events

Why "Snowfall" Is Misleading

• Precipitation ≠ snowfall: Measured as water equivalent; snow depth varies wildly with wind
• Wind redistribution: Katabatic winds (50-100+ mph) scour and deposit — "surface mass balance" ≠ precipitation
• Accumulation ≠ precipitation: Net accumulation includes sublimation, blowing snow export

Ice Sheet Mass Balance

What matters for sea level: net mass balance = accumulation - (ice discharge + basal melt + sublimation). Currently negative (~150 Gt/yr loss) — accelerating.

Measurement

• Automatic weather stations (AWS)
• Ice cores (annual layers = paleoclimate record)
• Satellite altimetry (ICESat, CryoSat)
• GRACE/GRACE-FO gravity measurements

Antarctica's "snowfall" is a technical glaciological variable—not a weather forecast metric. The continent is cold, dry, and losing ice.