- Who
- Clark Fork River valley
- Where
- United States ()
- When
On the night of 27 January 1887, a fierce winter storm dropped snowflakes described as "larger than milk pans" over the Clark Fork River valley, in the vicinity of a ranch owned by Matt Coleman, near Missoula in Montana, USA. Reports suggest that they were up to 1 ft 3 in (38 cm) wide and 8 in (20 cm) thick.
Snowflakes are conglomerations of smaller snow crystals that clump together. The largest individual snow crystal measured was 10 mm (0.39 in) from tip to tip, as documented by Professor Kenneth Libbrecht (USA) in Cochrane, Ontario, Canada, on 30 December 2003.