| OCR Text |
Show 8 k. Also close observation to determine the moment of the inevitable change in air flow from south to north, or the reverse. 5. Determining the type of old snow surface at all release zones, density and volume of new snow, together with new snow types and specific stratification of the new layers; particularly telltale ice or graupel layers. 6. Checking total new snow depth and densities against past slide histories to determine times of critical instability. INSTRUMENTATION Instruments for these necessary observations can be comparatively simple. At the time of this writing, few of our tools are of commercial manufacture. Three specific observation sites have been set up. The first is at Baldy Notch ( elev. 78OO1) on the divide between ocean and desert influences. Its primary function is to gather data in the upper accumulation zones, and to detect first indications of a change in direction of air movement. At present a wind sock, made of silk on wire hoop, on a removable mast, indicates wind direction. The standard annommeter proved unsatisfactory due to Icing during heavy fog. The wind sock can be removed during foul weather, and used only for periodic checks. Overflow cans from a standard rain gauge are used to compute water content of new snow fall. Core samples can be collected from the storm stake, the contents melted by immersing the can in a two gallon bucket partially fu11 of hot water, and the ratio computed from reading the depth on storm total stake. |
