Mountain permafrost
At high elevations in mid-latitude mountains, permafrost is
widespread where the mean annual air temperature is below
–3°C. It often exists far below the altitudes to which glaciers ex-
tend, and even below the tree line in continental areas. Moun-
tain permafrost exists in different forms – in steep bedrock, in
p
e
rock glaciers, in debris deposited by glaciers or in vegetated
r
m
a
f
r
soil, and contains variable amounts of ice. Since topography
o
s
t
causes large variability in local climate, snow cover, and ground colder
and surface properties through the processes of erosion, trans-
port and deposition, mean annual ground temperatures in
mountain regions can vary by 5–8 °C over distances as small as
100 m (Figure 7.8). For this reason, the distribution and charac-
teristics of permafrost in mountain regions are very patchy.
Permafrost influences the evolution of mountain landscapes
and affects human infrastructure and safety. Permafrost warm-
warmer
ing or thaw affects the potential for natural hazards such as
rock falls, debris flows and secondary events triggered by them
Figure 7.8: Temperatures in a mountain range containing per-
and also affects the topography itself in steep terrain. As in
mafrost (blue colours bordered by the black line), ranging from
Arctic permafrost regions, construction in mountain perma-
colder (blue) to warmer (red). Steep terrain and strong variability
frost regions requires special precautions and warming perma-
in surface temperatures are typical of mountain permafrost. The
frost poses problems to infrastructure. Mountain permafrost
cross section in the foreground shows the complex distribution
also contains valuable information on climate change. The
of subsurface temperatures characteristic of mountains, with the
presence of permafrost, in an actively moving rock glacier for
isotherms (lines linking points of equal temperature) nearly verti-
example, indicates a relatively cold climate, therefore inactive
cal in the ridge of the mountain. In the background, the colours
or fossil rock glaciers point to past colder climates. Measure-
on the mountain surface illustrate the strong variability in ground
ments of permafrost temperature, as well as providing infor-
temperatures caused by differences in elevation, exposure to the
mation on present-day permafrost stability, offer data on past
sun, snow cover and ground properties. In the far background,
climate changes.
one can only guess at this complex pattern of permafrost distri-
bution because permafrost is invisible at the ground surface.
Source: S. Gruber, photo from Christine Rothenbühler
Mountain permafrost contains large quantities of stored km
3
while the estimate of ground ice volume is about
fresh water in the form of ice. Mountain permafrost 280 km
3
for one area of the Tien Shan Mountains
80,81
.
within debris deposited by glaciers, or in rock glaciers Considering the continued glacier recession in Central
and other coarse blocky material has especially high ice Asia (see Chapter 6B), the melt waters from permafrost
content (up to 80 per cent of the total volume). The total could become an increasingly important source of fresh
volume of surface ice has been reported at about 462 water in this region in the near future.
194 GLOBAL OUTLOOK FOR ICE AND SNOW
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232  |  Page 233  |  Page 234  |  Page 235  |  Page 236  |  Page 237  |  Page 238