Scuba/Altitude

Depth Table

Feet	1000	2000	3000	4000	5000	6000	7000	8000	9000	10000
10	10	11	11	12	12	12	13	13	14	15
20	21	21	22	23	24	25	26	27	28	29
30	31	32	33	35	36	37	39	40	42	44
40	41	43	45	46	48	50	52	54	56	58
50	52	54	56	58	60	62	65	67	70	73
60	62	64	67	69	72	75	78	81	84	87
70	72	75	78	81	84	87	91	94	98	102
80	83	86	89	92	96	100	103	108	112	116
90	93	97	100	104	108	112	116	121	126	131
100	103	107	111	116	120	124	129	134	140	145
110	114	118	122	127	132	137	142	148	153	160
120	124	129	134	139	144	149	155	161	167	174
130	135	140	145	150	156	162	168	175	181	189

Ascent Rate At Altitude

30 feet per minute at all altitudes above sea level, verses 60 feet per minute at sea level

How To Find Your Pressure Group After Arriving At Altitude

If your starting altitude is less than dive altitude then add 2 pressure groups for each 1000 feet of altitude you increase.

If starting at altitudes of 4000 or higher, add 4 pressure groups for each 1000 feet of altitude increase.

If diving at an altitude of 8000 feet or greater wait 6 hours before diving.

Repetitive Diving

When diving at altitude it is recommended to limit your diving to no more than 2 dives per day.

Safety Stop Requirement

A safety stop is required for all dives at altitude. The depth of the safety stop changes with altitude. Refer to the above chart for correct depth.

Depth Gauges

Your depth gauge or computer must be adjusted for altitude diving. If you gauge cannot be adjusted then use the following formula to convert the closed bourdon tube gauge to get actual depth.

Depth Shown in feet + 1 foot + (1 foot per 1000 feet above sea level) = Actual depth

Source

http://utahscubadiver.com/wp-content/uploads/2012/04/AltitudeTables.pdf