As wind speed increases, your body loses heat more rapidly, making the air feel colder than it really is. The combination of cold temperature and high wind can create a cooling effect so severe that exposed flesh can freeze.
WINDCHILL TABLE
TEMPERATURE (°F)
|
wind speed (mph)
|
Calm |
35 |
30 |
25 |
20 |
15 |
10 |
5 |
0 |
-5 | -10 |
–15 |
–20 |
–25 |
–30 |
–35 |
|
5 |
31 |
25 |
19 |
13 |
7 |
1 |
–5 |
–11 |
–16 |
–22 |
–28 |
–34 |
–40 |
–46 |
–52 |
|
|
10 |
27 |
21 |
15 |
9 |
3 |
–4 |
–10 |
–16 |
–22 |
–28 |
–35 |
–41 |
–47 |
–53 |
–59 |
|
|
15 |
25 |
19 |
13 |
6 |
0 |
–7 |
–13 |
–19 |
–26 |
–32 |
–39 |
–45 |
–51 |
–58 |
–64 |
|
|
20 |
24 |
17 |
11 |
4 |
–2 |
–9 |
–15 |
–22 |
–29 |
–35 |
–42 |
–48 |
–55 |
–61 |
–68 |
|
|
25 |
23 |
16 |
9 |
3 |
–4 |
–11 |
–17 |
–24 |
–31 |
–37 |
–44 |
–51 |
–58 |
–64 |
–71 |
|
|
30 |
22 |
15 |
8 |
1 |
–5 |
–12 |
–19 |
–26 |
–33 |
–39 |
–46 |
–53 |
–60 |
–67 |
–73 |
|
|
35 |
21 |
14 |
7 |
0 |
–7 |
–14 |
–21 |
–27 |
–34 |
–41 |
–48 |
–55 |
–62 |
–69 |
–76 |
|
|
40 |
20 |
13 |
6 |
–1 |
–8 |
–15 |
–22 |
–29 |
–36 |
–43 |
–50 |
–57 |
–64 |
–71 |
–78 |
|
|
45 |
19 |
12 |
5 |
–2 |
–9 |
–16 |
–23 |
–30 |
–37 |
–44 |
–51 |
–58 |
–65 |
–72 |
–79 |
|
|
50 |
19 |
12 |
4 |
–3 |
–10 |
–17 |
–24 |
–31 |
–38 |
–45 |
–52 |
–60 |
–67 |
–74 |
–81 |
|
|
55 |
18 |
11 |
4 |
–3 |
–11 |
–18 |
–25 |
–32 |
–39 |
–46 |
–54 |
–61 |
–68 |
–75 |
–82 |
|
|
60 |
17 |
10 |
3 |
–4 |
–11 |
–19 |
–26 |
–33 |
–40 |
–48 |
–55 |
–62 |
–69 |
–76 |
–84 |
EXAMPLE: When the temperature is 15°F and the wind speed is 30 miles per hour, the windchill, or how cold it feels, is –5°F. For a Celsius version of this table, visit Almanac.com/WindchillCelsius.
–courtesy of National Weather Service
HOW TO MEASURE EARTHQUAKES
In 1979, seismologists developed a measurement of earthquake size called MOMENT MAGNITUDE. It is more accurate than the previously used Richter scale, which is precise only for earthquakes of a certain size and at a certain distance from a seismometer. All earthquakes can now be compared on the same magnitude scale.
MAGNITUDE DESCRIPTION EFFECT
LESS THAN 3 ................................ MICRO GENERALLY NOT FELT
3–3.9 ............................................. MINOR OFTEN FELT, LITTLE DAMAGE
4– 4.9 ............................................. LIGHT SHAKING, SOME DAMAGE
5–5.9 .......................................... MODERATE SLIGHT TO MAJOR DAMAGE
6–6.9............................................ STRONG DESTRUCTIVE
7–7.9 .............................................. MAJOR SEVERE DAMAGE
8 OR MORE .................................... GREAT SERIOUS DAMAGE