62 BULLETIN 1059, U. S. DEPARTMENT OE AGKICULTURE. 



the entire range of types, read at the end of each month by the 

 rangers on whose districts they are located. The major portion of 

 these scales are in timbered areas because of the necessity of some 

 protection to secure a representative snow cover (90). Many of 

 them, however, are not actually in the forest but in small parks or 

 openings, and some are in patches of aspen or coniferous reproduc- 

 tion. The cover conditions are classified as (a) normal forest cover 

 of mature or nearly mature trees, (b) partial cover, as given by 

 aspen, reproduction, or scattered trees which shade the snow to some 

 extent, and (c) no cover, as in parks or openings. For each snow 

 scale a complete description of the cover and surroundings is ob- 

 tained. The essential features of this description are listed on the 

 record card for each scale, and the cards are filed serially according 

 to scale numbers, each card carrying the depth and density record 

 for 12 years. 



2. The reports from rangers are submitted at the end of each 

 month on postal cards, of which the following is a sample: 



Snow Scale No. — . 



Snow Report National Forest, for the end of 19 — , county 



, main drainage , local stream . 



Depth at scale, inches. Average in vicinity, inches. 



Is depth more (+) or less ( — ) than normal for this time of year? 



Density measurement: Depth of snow in tube, (inches and tenths); water 



equivalent of tube contents, (inches and hundredths, aa shown by spring 



balance). 



^Density estimate, — per cent. (Light, fresh snow should be estimated at 6 to 8 



per cent; settled, dry snow at 8 to 15 per cent; drifted, compact snow at 15 to 20 

 per cent; frozen or wet snow, with ice at bottom, at 20 to 40 per cent 



The above observations were made by ("myself ' or name of other party | 



on 19—. 



(Signature) 



Fun si J!<inr;,r. 

 * Not to be filled by officers having density apparatus. 



3. Snow depths are read at each scale by simply sighting over the 

 general surface of the snow and noting the intersection of this plane 

 with the graduations on the scale. 



4. For most localities, the density of the snow is estimated from 

 the descriptive data given on the card. Each ranger is expected to 

 make occasional rough tests to determine density, so that lie will 

 become proficient in estimating under varying conditions. A few 

 rangers are now furnished with density-measuring apparatus (91) 

 and the number of such apparatus is to be increased as conditions 

 and funds warrant. The apparatus consists simply of a tube in 

 which a core of snow may be taken (its length being noted on the 

 scale outside the tube), and a balance graduated for inches of water. 

 The weight in inches divided by the depth in inches gives the densil y. 



