freshly fallen snow and in their flight had moved 

 in old channels that had been followed and per- 

 haps formed by hundreds of slides in years gone 

 by. Slides of this kind — those which accom- 

 pany or follow each storm and which promptly 

 make away with new-fallen snow by carrying 

 it down through stream-channels — may be 

 called Storm, or Flood, slides. These usually 

 are formed in smooth gulches or on steep 

 slopes. 



The other kinds of slides may be called the 

 Annual and the Century. In places of rough 

 surface or moderate slope there must be a large 

 accumulation of snow before a slide will start. 

 Weeks or even months may pass before storm 

 and wind assemble sufficient snow for a slide. 

 Places of this kind commonly furnish but one 

 slide a year, and this one in the springtime. At 

 last the snow-drifts reach their maximum; 

 warmth assists starting by melting snow-cor- 

 nices that have held on through the winter; these 

 drop, and by dropping often start things going. 

 Crags wedged off by winter ice are also re- 

 leased in spring; and these, in going recklessly 



87 



