RYG Rules

Category	Yellow	Red
Personnel	Temp < 20º F Wind chill < -20º F Heat Stress Index (HSI) >=90° Thunderstorms (winds < 50kt, lightning, small hail) Winds > 30kts	Wind chill < -75º F Heat Stress Index (HSI) >=105° Severe Thunderstorms (winds > 50kt, frequent lightning, hail > 1/2 inch) Winds > 50kts
Cat 1 Watercraft Floating Causeway, RRDF, SLWT, Causeway Ferry	Sea State >= 2 MSI >= 5 Visibility < 1 mile Freezing drizzle Winds > 30 kts	Sea State >= 3 MSI >= 6 Visibility < 1/2 mile Freezing rain Winds > 50 kts
Cat 2 Watercraft LCM, LARC, 65' Tug, 100' Tug	Sea State >= 2.5 MSI >= 7 Visibility < 1 mile Freezing drizzle Winds > 30 kts	Sea State >= 3.5 MSI >= 8 Visibility < 1/2 mile Freezing rain Winds > 50 kts
Cat 3 Watercraft LCU 2000, LSV, 128' Tug	Sea State >= 3 MSI >= 10 Visibility < 1 mile Freezing drizzle Winds > 30 kts	Sea State >= 4 MSI >= 12 Visibility < 1/2 mile Freezing rain Winds > 50 kts
Vehicle	Visibility < 1 mile Heavy Rain	Visibility < 1/2 mile Freezing precipitation Snow/Ice accumulation on roads Winds > 50 kts

Heat Stress Index (HSI):

HSI, like the Wet Bulb Globe Temperature (WBGT) units use on a daily basis, is an indicator of dangerous heat conditions. Like WBGT, HSI takes into account air temperature and humidity. However, it does not account for 2 parameters that WBGT does--sun shine and the cooling of the wind (parameters we can't currently forecast). HSI should be used as an indicator of potential heat danger so appropriate preparations can be made before a dangerous situation arises (e.g. ensuring extra water is available, adjusting training schedules, etc.). Units should continue to use WBGT observations IAW SOPs to determine water requirements and required duty modifications.

HSI 80º to 89º: Fatigue possible with prolonged exposure and physical activity.

HSI 90º to 104º: Sunstroke, heat cramps, or heat exhaustion possible with prolonged exposure and physical activity.

HSI 105º to 129º: Sunstroke, heat cramps, or heat exhaustion likely; heatstroke possible with prolonged exposure and physical activity.

HSI > 130º: Heatstroke or sunstroke imminent.

Wind Chill: (Info on New Wind Chill)

Temperature (degrees Fahrenheit)

Calm	40	35	30	25	20	15	10	5	0	-5	-10	-15	-20	-25	-30	-35	-40	-45
5	36	31	25	19	13	7	1	-5	-11	-16	-22	-28	-34	-40	-46	-52	-57	-63
10	34	27	21	15	9	3	-4	-10	-16	-22	-28	-35	-41	-47	-53	-59	-66	-72
15	32	25	19	13	6	0	-7	-13	-19	-26	-32	-39	-45	-51	-58	-64	-71	-77
20	30	24	17	11	4	-2	-9	-15	-22	-29	-35	-42	-48	-55	-61	-68	-74	-81
25	29	23	16	9	3	-4	-11	-17	-24	-31	-37	-44	-51	-58	-64	-71	-78	-84
30	28	22	15	8	1	-5	-12	-19	-26	-33	-39	-46	-53	-60	-67	-73	-80	-87
35	28	21	14	7	0	-7	-14	-21	-27	-34	-41	-48	-55	-62	-69	-76	-82	-89
40	27	20	13	6	-1	-8	-15	-22	-29	-36	-43	-50	-57	-64	-71	-78	-84	-91
45	26	19	12	5	-2	-9	-16	-23	-30	-37	-44	-51	-58	-65	-72	-79	-86	-93
50	26	19	12	4	-3	-10	-17	-24	-31	-38	-45	-52	-60	-67	-74	-81	-88	-95
55	25	18	11	4	-3	-11	-18	-25	-32	-39	-46	-54	-61	-68	-75	-82	-89	-97
60	25	17	10	3	-4	-11	-19	-26	-33	-40	-48	-55	-62	-69	-76	-84	-91	-98

Wind Chill	Possible Effects
30°F>	Chilly: Generally unpleasant
15°-30°F	Cold: Unpleasant
0°-15°F	Very Cold: Very unpleasant
^-20°- 0°F	Bitter Cold: Frostbite possible.
^-20°- ^-60°F	Extremely Cold: Frostbite likely. Outdoor activity becomes dangerous.
^-60°<	Frigidly Cold: Exposed flesh will freeze within half a minute.

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