An Etymological Dictionary of the German Language/Schloße
Schloße, f., ‘hail, hailstone, sleet,’ from the equiv. MidHG. slôȥe, f., slôȥ (m. and n.?); OHG. *slôȥa is wanting; comp. Du. slote (OSax. *slôta), AS. *slŷt, *slête, E. sleet (Goth. *slauti- is wanting). The origin of the cognates is obscure; it is scarcely derived from the root slū̆t, ‘to lock,’ as if hail were regarded as ‘that which is bound together compared with the soft snowflakes and the streaming rain.’ —