Hummer 2004 H2 Owner's Manual page 252

Also, specifications required that the HUMMER H2 be
able to traverse a 40% (22°) side slope at 6 mph
(9.7 km/h) while fully loaded on high friction surfaces.
4-26
The HUMMER H2 can climb a 16 inch (40.6 cm)
vertical step. Step climbing is best done by approaching
the step at an angle rather than straight on.