How hard it is snowing, quantified by accumulation per hour.
Credit: Sawtooth Avalanche Center
Heavier snowfall rates equate to rapid stress on the snowpack and often result in increased avalanche activity. Practitioners describe snowfall rates as very light (less than 1 cm of accumulating snow per hour), light (about 1 cm per hour), moderate (about 2 cm per hour), heavy (about 5 cm per hour), and very heavy (about 10 cm per hour). Heavy snowfall rates (more than 2” or 5 cm per hour) are a potential sign of instability.
Very Light Snowfall
Light Snowfall
Moderate Snowfall 
Heavy Snowfall 
