|
WIND CHILL |
Cold is a far greater threat to survival than it appears. It decreases your ability to think and weakens your will to do anything except to get warm. Cold is an insidious enemy; as it numbs the mind and body, it subdues the will to survive.
Cold makes it very easy to forget your ultimate goal--to survive.
Wind chill is used to warn people of dangerous conditions due to low temperatures and winds, so wind chill is not normally calculated for air temperatures above 5C or wind speeds below 2mph. It was something I was introduced to as a Scout when walking over and around Kinder Scout. At the time I foolishly asked how it was calculated and was met with many a blank face, and some clearly inaccurate answers.
Many years later, and wishing I had never asked the question the answer came back as:
WCT = 13.12 + 0.6215T - 11.37V0.16 + 0.3965TV0.16
Where:
WCT is the wind chill temperature in C
T is the air temperature in C
V is the wind speed at 10m in km/h
V = V1.5 * 1.5 where V1.5 is the wind speed at 1.5m
To make life a little easier, tables have been published to help gauge the effect of wind on temperatures, as can be found below.
|
Wind Chill Table |
|
|
Air Temperature C |
|||||||||||
|
Wind Speed in mph (at 1.5m ) |
5 |
0 |
-5 |
-10 |
-15 |
-20 |
-25 |
-30 |
-35 |
-40 |
-45 |
-50 |
|
2 |
4 |
-2 |
-7 |
-13 |
-18 |
-24 |
-30 |
-35 |
-41 |
-47 |
-52 |
-58 |
|
4 |
3 |
-3 |
-9 |
-15 |
-21 |
-27 |
-33 |
-39 |
-45 |
-51 |
-57 |
-63 |
|
6 |
2 |
-4 |
-10 |
-17 |
-23 |
-29 |
-35 |
-41 |
-47 |
-54 |
-60 |
-66 |
|
8 |
1 |
-5 |
-11 |
-18 |
-24 |
-30 |
-37 |
-43 |
-49 |
-55 |
-62 |
-68 |
|
10 |
1 |
-6 |
-12 |
-19 |
-25 |
-31 |
-38 |
-44 |
-51 |
-57 |
-63 |
-70 |
|
12 |
0 |
-6 |
-13 |
-19 |
-26 |
-32 |
-39 |
-45 |
-52 |
-58 |
-65 |
-71 |
|
14 |
0 |
-7 |
-13 |
-20 |
-27 |
-33 |
-40 |
-46 |
-53 |
-60 |
-66 |
-73 |
|
16 |
-1 |
-7 |
-14 |
-21 |
-27 |
-34 |
-41 |
-47 |
-54 |
-61 |
-67 |
-74 |
|
18 |
-1 |
-8 |
-14 |
-21 |
-28 |
-35 |
-41 |
-48 |
-55 |
-62 |
-68 |
-75 |
|
20 |
-1 |
-8 |
-15 |
-22 |
-28 |
-35 |
-42 |
-49 |
-56 |
-62 |
-69 |
-76 |
|
22 |
-1 |
-8 |
-15 |
-22 |
-29 |
-36 |
-43 |
-49 |
-56 |
-63 |
-70 |
-77 |
|
24 |
-2 |
-9 |
-16 |
-22 |
-29 |
-36 |
-43 |
-50 |
-57 |
-64 |
-71 |
-78 |
|
26 |
-2 |
-9 |
-16 |
-23 |
-30 |
-37 |
-44 |
-51 |
-58 |
-65 |
-71 |
-78 |
|
28 |
-2 |
-9 |
-16 |
-23 |
-30 |
-37 |
-44 |
-51 |
-58 |
-65 |
-72 |
-79 |
|
30 |
-2 |
-9 |
-16 |
-24 |
-31 |
-38 |
-45 |
-52 |
-59 |
-66 |
-73 |
-80 |
|
Frostbite may occur in 30 minutes or less |
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The above table is calculated using the wind chill equation detailed earlier and adopted by the US and Canadian weather services in 2001
For a more accurate reading, a calculator available in 16bit or 32bit formats can be downloaded from the link below. (Please note this calculator is not provided by 142group.net)