inhomogeneous distribution of ice masses. Dur- 
ing the spring only a small amount of heat must 
be added to raise the temperature of the entire 
snowpack to the melting point, yet it takes a 
long time for this to happen. Throughout this 
time the snow structure can undergo significant 
changes from only a few days of abnormally 
warm weather. The warm spell in early May 
1972 reduced the amount of heat required to 
only one-third of the amount required in mid- 
April. However, a few cool days in mid-May 
doubled the amount required. Furthermore, ice 
lenses produced by the warm spell in early May 
remained in the snow for a month. 
Distribution of Snow and Windblown Dust 
The locations of traverses and of snow 
sample sites are indicated in Fig. 1. Some data 
on snow characteristics were presented above. A 
summary of the data obtained mainly from 
vertical core samples at 176 sample sites is 
presented in Table 5. To facilitate digestion of 
these data, they will be discussed according to: 
(a) water equivalent, (b) snow drifting and, (c) 
dust drifting. 
Water equivalent of the snow 
It is not easy to simply cite a single value for 
the amount of snow on the tundra. This is 
because of the variability in snow depth and 
density produced by wind drifting and the com- 
plexity of small-scale topographic features. We 
have attempted to determine average values for 
snow depth and density which can be used to 
calculate the water equivalent of snow on the 
tundra apart from drift traps such as banks of 
lakes and rivers. 
The average depth of undisturbed snow on 
the tundra at Prudhoe Bay in May 1972 was 
32 cm. This value is based on 871 probe depth 
values that were all made more than 150 m from 
any road or other disturbance that may cause 
drifting. 
The average density, based on the detailed 
studies shown in Figs. 7 and 9, was 0.309 g 
cm. The water equivalent from these studies 
averaged 12.4 cm HO (Table 2, excluding the 
drift case of Fig. 9a). If we use the average 
density value from these studies together with 
the average depth of 32 cm, we obtain an 
average value of 9.9 cm water equivalent. 
23 
Temperature, °C 
SG) GG. Sie sie alo) -8 -6 -4 = (0) 
50 Lae] tl pL aa oa (sna me | (anna 
L ane == 
| 
\ 
i 4 
| 
€ | 
° 4 =H 
= 4 
a | 
: 7 
Zz 
7 
FZ 
Ma 
| 4 (eee (fae pee 1 
14 Apr '72 16 May '72 
(A) E of Pingo (D) 200m E of P2 
1 (E) 300m E of P2 
14 May '72 
| June ‘72 
(F) Generalized 
Temperature Profile 
Fig. 10. Summary of temperature profiles 
from Figs. 7 and 9. 
(B) 40m E of P2 
(C) 90m Eof P2 
Table 3 
Calculated range of temperature in the snow, using three 
values for diffusivity, a , in units of cm2sec"! 
Depth below 
snow surface Temperature range 
(cm) 
Temp °C 
ye We fe 2 GA eB 
(e) es ey es ee es ee =} 
lo ] 
Snow 
Depth 20 : 
cm 
30 
40 4 
Fig. 11. Calculated daily temperature ranges. 
