Wind Chill Table with info on hypothermia and frostbite

[JP]

Wind Chill Table

How to use this table
by JP Honeywell

I created this table to help you understand the dangers of hypothermia and frostbite when riding a motorcycle. I was disappointed that most windchill charts start at a temperature not much above freezing. Since we've all noticed that there is an appreciable windchill at temperatures many would consider normal I thought that starting at a warmer temperature would be worthwhile.

I used the official formula that everyone else was using to create their windchill charts. That formula, if you are interested is listed below the chart. I also have the chart in an Excel 97 spreadsheet. If you need a copy of it I could be persuaded to email it to you.

One of the things I noticed is that at 100 degrees F the wind offers no relief at all. Some Iron Butt Association members lead me to believe that this is accurate. When crossing desert portions of the country it is cooler, they tell me, to keep your skin covered by a jacket. Apparently the insulating qualities work to keep the excess heat out much the same way it keeps heat in during colder temperatures. Or maybe it was just keeping the sun off that helped. It does make sense if you think about it. Blowing 102 degree air at a 98 degree target will eventually raise the temperature to 102 degrees. But I only present this as anecdotal evidence.

Another interesting characteristic that this chart points out is that above 40 mph the temperatures seem to stabilize. Then they actually increase a bit with the rise in wind speed. Is that accurate? Again, I don't know. Maybe it is. Looking at the formula, it is rather complex. Someone stayed up late figuring that one out. My belief is that it really doesn't matter because the difference is not very great. Even at the coldest extremes there's only an eight degree difference. And when you're feeling -95F can you really tell the difference between that and -103F. I probably couldn't.

I hope you find this useful.

Wind speed (in mph)	still air temperature (degrees F)
	100	90	80	70	60	50	40	30	20	10	0	-10	-20	-30
	wind chill temperature
0	100	90	80	70	60	50	40	30	20	10	0	-10	-20	-30
5	100	90	79	69	58	48	37	27	16	6	-5	-15	-26	-36
10	102	90	77	65	53	41	28	16	4	-9	-21	-33	-46	-58
15	103	90	76	63	49	36	22	9	-4	-18	-31	-45	-58	-72
20	104	89	75	61	47	33	18	4	-10	-24	-39	-53	-67	-81
25	104	89	75	60	45	30	15	1	-14	-29	-44	-59	-73	-88
30	104	89	74	59	44	28	13	-2	-17	-32	-48	-63	-78	-93
35	105	89	74	58	43	27	12	-4	-19	-35	-51	-66	-82	-97
40	105	89	73	58	42	26	10	-5	-21	-37	-53	-68	-84	-100
45	105	89	73	57	42	26	10	-6	-22	-38	-54	-70	-86	-101
50	105	89	73	57	41	25	9	-7	-23	-39	-55	-71	-86	-102
55	105	89	73	57	41	25	9	-7	-23	-39	-55	-71	-87	-103
60	105	89	73	57	41	25	9	-7	-23	-39	-55	-71	-87	-102
65	105	89	73	57	41	26	10	-6	-22	-38	-54	-70	-86	-102
70	105	89	73	58	42	26	10	-6	-21	-37	-53	-69	-85	-101
75	105	89	74	58	42	26	11	-5	-21	-36	-52	-68	-83	-99
80	105	89	74	58	43	27	12	-4	-19	-35	-50	-66	-81	-97
85	105	89	74	59	43	28	13	-3	-18	-33	-49	-64	-79	-95
Note: Wind speeds greater than 40mph add little to the effect
	No protection required			Little danger if properly clothed			Increasing Danger of freezing exposed skin				Great Danger of freezing exposed skin
Formula used to calculate Wind chill Wind chill = 91.4 - (0.474677 - 0.020425 * W + 0.303107 * SQRT(W)) * (91.4 - T) where W = wind speed (mph) and T = temperature (° F)

Frostbite: Is the crystallization of tissue fluid cased by exposure to cold below freezing. Most common areas of frostbite are the face, nose, ears, hands and feet. The symptoms include redness and pain in the early stages, followed by a waxy white appearance, numbness and the skin may feel stiff and even brittle.

 

PREVENTION OF COLD INJURY

To Stay Warm Remember The Word C-O-L-D

C - Cleanliness and Care: Feet, Socks, and clothing are warmer when clean. Constant foot care is imperative.

O - Overheating: Prevent overheating by adjusting your clothing to the job being performed.

L - Loose and Layered: Loose-fitting clothing insures good circulation and insulation. Clothing in layers assures air spaces which hold body heat. Again, allows the person to adjust the number of layers to the temperature and activity being performed.

D - Dampness: Any wet garment is a cold garment, just as tight-fitting garments are cold producing garments. Keep clothing dry.

* Use the Buddy system, this is the best way to prevent cold injury. If you start feeling cold do some exercises until you start feeling warm again.

FIRST AID FOR COLD INJURIES

1. Get individual off their feet.
2. Get individual into warm dry clothing.
3. Get individual warm fluids to drink (NO ALCOHOLIC BEVERAGES)
4. Do not smoke.
5. Keep the effected area clean, warm and dry. Do not allow to REFREEZE. If you cannot keep area warm, leave it frozen.
6. Do not rub affected area.
7. Evacuate through medical channels ASAP.

 

HYPOTHERMIA

The condition of low internal body heat dropping steadily from a healthy 98.6, and if not reversed, can bring fatal consequences. Hypothermia can develop without much warning. Dress for the weather and avoid getting wet or damp.

 

Generally characterized by uncontrolable shivering, mild hypothermia can be treated by drinking warm liquids, and by taking a hot shower. A more serious condition requires medical attention.