G2 BULLETIN 1059, U. S. DEPARTMENT OF AGRICULTURE. 
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 ( -f- ) 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, as 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) , 
Forest Ranger. 
*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 he 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 density. 
