474 MONTHLY WEATHER REVIEW. SEPTEMBER, 1922
it advances f a r inland, the reviewer makes a mental reservation as to just how fv this process is fulfilled in nature, especially on the Pacific coast. In the theory of the formation of anticyclones no account is taken of the effect of radiation. The influence of radiation in the dry regions of the far West is believed to play a large part in the formation and maintenance of anticyclones y1 that region. It is free1 conceded that the researches of the meteor-
in advance, yet it can not be sai that the theory they advance is complete and satisfying. The remewer s
experience as a forecaster leads h m to the opinion that
!
ologists of t % e Bergen Institute re resent a decided step
for the United States, for example, the occurrence of precipitation in connection with cyclones and anti- cyclones is not fully explained by the Bjwknes theow; nioreover, some doubt has been expressed in an unpub- lished manuscri t by Mr. Herbert L. Choate, of the
Plains States at least, of the cold front. and the wind circulation on the front of the idealized cyclone of B’erknes. In any event further study of the kite and pdot-balloon data now available will doubtless lead to
a better understanding of the physical processes involved in the origin and maintenance of cyclones and anti- cyclones.
Drexel (Nebr.) R ite station, as to the existence in the
FOOT-LAYER DENSITIES OF SNOW.’
By H. F. ALPa, Meteorologist.
[Weather Bureau, Reno, Nev., Septembep’ 19,1922.1
This special investigation of snow densities was begun in the fall of 1916 and continued each season until its com letion in the spring of 1921. d e measurements were n?ade at Summit, Calif., about
40 miles west of Reno, at an elevation of 7,019 feet. Summit station is located near the easterly end of Sum- mit Valley, which is about 3 miles long and 1 mile wide. This valley is fairly well timbered and the rim of the sur-
rounding mountams is approximately 1,000 feet above
. This region is considered an ideal location for
any kin of snow mveati ations, as the average annual snowfall is 442 inches, whic is the greatest seasonal snow- fall recorded in the United States. Moreover, the snow- fall is comparatively free from drifting effects and therc- fore the snow cover is remarkably uniform in de th. The
purposes is undoubtedly greater than from any other regon in the United States. Fifteen miles to the soutli- east and a proximately 800 feet lower, lies Lake Talioe,
United States. The work represents a total of 24 trips to Summit, during which 659 measurements were made. The first five trips were made by H. F. Alciatore and 0. H. Ham- monds, and be innin with April, 1917, the work was
5l
the vallT
run-off from snow fields for irrigation and hy B roelectric
the fargest % ody of fresh water at that elevation in the
carried on by t %E e aut or and 0. H. Hammonds.
TABLE l.-Dales of trips and total depth of motu roarer in inc.lrrs.
smson.
1018-10 ..............
1-a .............. .......... ........................ ..........
I I
imsm
No(e.-?&ammea& taken at Summit, Calif., elevation, 7,010 feet.
The primary ob‘ect of the investigation was to test the accuracy of the dengler formula and ascertain whether the formula has any practical working value. This for- mula states in substance that the density of any given layer of snow bears a certain relation to the density of the top layer, depending upon the depth of the gwen
1 Cf E F Alofatore La meosurememts of snow on ground near Summit, Calif. LIo. Wrk& REV. 1: S l L WEpgla, Rita Dfc Sped- Dkhk dw Sckneer. Berlh, 1014.
layer below the surface. After starting the investigation, it was found that an escellent opportunity was given for the study of the snow cover thro hout the entire season.
density of each 12-inch layer from the ground up. For this work the following instruments were used: A Weather Bureau snow sampler 16 inches long and 4.002
inches in diameter, a Weather Bureau sprmg balanm weighing in fiftiet,hs of a pound, and a piece of apparatus called a “snow slicer” made of galvanized iron, about
14 by 14 inches, with a sharp semicircular edge on the side opposite two wooden handles. In order to make layer measurements, a smooth vertical section of the entire snow cover was obtained by dig ing a trench. The &inch layers were then marked on t % e face of this
inserted first beneath
above the slicer was then
the slicer formed the bottom of each layer while being sampled, accurate foot-layer measurements were ob- tained. Two or three samples of each layer were taken and the resulting avera e used in all cases.
were made to Summit beginning with November. his was the season when the snow cover reached its eatest depth, 168 inches on March 15. Table 1 shows g;f t e remarkable uniformity in the monthly increase of the snow cover from November to February, and decrease from March to May. This was an ideal season for snow work and it was fortunate that density measurements were started during this season. As the snowfall during this season was practically normal both as to time of occurrence and amount, the records are considered of greater value than those of any other season during whch measurements were made. Five trips were made to Summit during the season of 1917-18. This was an unusual year. The highway over the summit was open until January 12, when it was closed by 32 inches of snowfall. The snowfall for the season to January 12 was the least on record, and it was the only year in the memory of oldtimers when the hghwa was o en on New Year’s day. On November 3, 1917, tge dept% of snow was 2.9 inches, and on January 2, 1918, the de th was 5.8 inches. (Fig. 1.) February storms were mo a er- ately heavy, and on the 26th a depth of 82.5 inches of snow was measured. (Fig. 2.) The results of each trip are given in Table 2.
Therefore, it resolved itself into T t e determination of the
section, beginning at
this layer was
succeeding layers was
Y
During the season o B 1916-17 seven tri
M. W. R., September, 1922. T o face p. 474. )
FIQ. 1.-Bare ground at Summit station, Janiiary 2,1918.
FIG. 2.-Vertical section of snow showing depth of 82.5 inches
B%bruary 26, I9
E
FIG. d.-Illustrating run-off beneath snow cover, Summit, Calif.
SEPTEMBER, 1922. MON'..LY WEATHER REVIEW. 475
1916-17. November.. ........ Decem- .......... January ............ Febmary ........... March .............. A ............... & ................
1917-18. November .......... December.. ............... January ............ February ........... March .............. April ...............
1818-19. Decembs .......... Janu8ry ............ February.. ................ March .............. ............... ................
19leaO. Decermbtv .......... January.. .................. February ............. .............. ............... ................
TABLE ' 2.--snoW density by I-foot luycta pound u p at Summit, Calv.
IPercentage of equivalent water.)
21 37 42 43 43 55 01
43
36 4 52
46
30 34
37 43 50
36
:. .... 47 51
55
lsao-al. J M U ~ ............ February.. ................. March .............. Ap rll ...............
41
48 46
-
1 t o 2
-
... 37 38 44 42 45 50
... ... ... 32 49 54
a5 30
34 44 4t9
32
45 48 58
47
51 52
..
... ...
...
-
2 1 3 to I to 3 1 4
I
4 4 4 3 48 51
62
........ ........ ........ 28 24 54 48 ........
........ 28 24
39 37 47 45
48 ....
35 ....
53 32 52 45 54 ....
........
....... .......
-
.. .I ...
...... ...... ...... 24 22 46 47 .......
....... ....... ....... 39 37 5 0 5 0
.......
6 7 to to 7 s
__
.-.I.-.
!
.-.I ---
16 I...
....... ......
... I...
......
..... . . -1:. . ,
... 1 .... 30 25
47 I ___. ... I .... I
!
...
... .... ....
B 2 4 / ........ ............... ~i 4 9 4 6 4 6 4 3 53 .... 1 ....I ....
During the season of 1918-19 five trips to Summit were made, the first being on Decebmer 31, when the de th of snow was 33 inches. The January snowfall was ligIt, but the snowfall during Februaz was heavy and a
depth of 122 inches was measured on arch 5 , which was the greatest of the season. Four tri s were made to Summit during the season of
of snow was 39 inches, and the ound was frozen to a
and the first half of February, the nest tnp was delayed until March 5 , when there was B depth of 68 inches on the ground. At this tinie the round was well moistened and not frozen. On A ril 13 t B e dept-h was 68 inches, and it was 36 inches on d y 13.
1919-20, t fl e h t being on December 31, when the depth
depth of 1 inch. As the snowfal ff was light in January
Only three trips to Summit were made during the
season of 1920-21. The first measurementa for this season were made on January 14, when the snow cover was 64 inches. The maximum de th of the season was
remained on the ground on Apnf29. The density of the snow cover in January was much greater than usual. The layer measurements prove that it is impossible to determine the density of the whole snow cover from the density of a layer on the surface. Wengler himself stated that in dee snow there are such breaks in uni- formity that a pedct law can not be established. This lack of uniformity in density is due to weather conditions durin the accumulation of the snow cover. In the in- tervaf between storms crusts of varying thickness and density are invariably formed, and such crusta were en- countered each season in the work at Summit. These crusts varied from a fraction of an inch to 10 inches in thickness, and some of them were almost solid ice in formation. The density of a la er of snow where incrus-
layers with no incrustation. €$ noting the relative position of certain c.rusts at different times, it urns proved tha,t the mow disappears simdtaneously from the top and the hottom. The mean density for the whole snow cover at Summit, CMif., as determined by the five seasons of investigations, is as follows:
97 inches on March 17, and a de t E of 63 inches of snow
tation was found was considera t 1 greater than adjacent
...... -- __
34 40
.... .....
Five years is a short period to establish accurate means, yet it is believed that records covering a lon er period of
fore, it is believed the water content of the snow cover at Summit, Calif., and adjacent regions can be determined a proximately at any time of the season b j applying
these values would hold good for other r0gions could be determined only by investigations in those regions. This is the fist detailed study of B snow cover during several consecutive sea.sons that has been made in this cour~tr~y, nnd t,he records obtained should add much to our limited knowledge of snow densities.
time would not change these values materi 3 ly. There-
t I! ese average densities to the depth. Whe er or not
A SIMPLE SNOW-DENSITY MEASURER.'
By W. W. KORHONEN.
[Tr8nSlatiOD by E. C. Frankenaeld.]
With the cooperation of Prof. G. Melander, I have con- structed for the determination of snow densit a new
more rapidly and simp1 than hitherto, and the measure- menta can be made in &e open air. It consists of a cyl- inder 50 om. in height, with a cross section of 100 cm.', a shovel, a sliding weight balance, and a hook by which the cylinder is attached to the balance. The balance has an arm 48 cm. in length, and the prisms, which are 4 cm. apart, can be pressed together for transportation by meam of two screws. The sliding weight wei hs 200 g., wherefore a snow mass of 10 g. ( = lmm. water % epth) cor- responds to a length of 2 mm. on the scale. The balance
measurer with which observations can be m K e much
I M e t e o r o l ~e Zeitschrlit,. JUM, 1922.
arm can be brought into a horizontal plane by meam of an indicator fastened to one of the prisms, whereupon the
readin will be found at the end of the slidin weight.
which corresponds to the water content of a layer of snow about 1 m~n. in thickness. For transport the bal- ance and hook are placed in the cylinder and this, to-
ether with the shovel, are packed into B narrow sack. h e observation is so carried out that the cylinder, after the snow sample has been cut in the prescnbed manner, is overturned, fastened with the hook to the balance, and weighed, so that the lid of the cylinder serves as a bottom.
There was freedom from the earlier errors of evapora- tion by reason of careless melting of the snow, the ad4e
The b 3 ance turns the scale distinctly for a weig % t of 2 g.,