AVAHI

avahi, the native name of a malagasy lemur (_avahis laniger_) nearly allied to the indri (_q.v._), and the smallest representative of the subfamily _indrisinae_, characterized by its woolly coat, and measuring about 28 in. in length, of which rather more than half is accounted for by the tail. unlike the other members of the group, the avahi is nocturnal, and does not associate in small troops, but is met with either alone or in pairs. very slow in its movements, it rarely descends to the ground, but, when it does, walks upright like the other members of the group. it is found throughout the forests which clothe the mountains on the east coast of madagascar, and also in a limited district on the northwest coast, the specimens from the latter locality being of smaller size and rather different in colour. the eastern phase is generally rusty red above, with the inner sides of the limbs white; while the predominant hue in the western form is usually yellowish brown. (see primates.) (r. l.*) avalanche (adopted from a french dialectic form, _avalance_, descent), a mass of snow and ice mingled with earth and stones, which rushes down a mountain side, carrying everything before it, and producing a strong wind which uproots trees on each side of its course. where the supply of snow exceeds the loss by evaporation the surplus descends the mountain sides, slowly in the form of glaciers, or suddenly in ice-falls or in avalanches. a mass of snow may accumulate upon a steep slope and become compacted into ice by pressure, or remain loosely aggregated. when the foundation gives way, owing to the loosening effect of spring rains or from any other cause, the whole mass slides downward. a very small cause will sometimes set a mass of overloaded snow in motion. thunder or even a loud shout is said to produce this effect when the mass is just poised, and swiss guides often enjoin absolute silence when crossing dangerous spots.