How do you ventilate a roof that has two different ridge heights?

Here is some general guidance for ventilating a roof with two different ridge heights.

The basic rule for ridge heights is: All ridges can be vented whether they run parallel or at angles to each other, however, if the ridges are more than 3 feet apart in height, only ventilate the higher ridge. The reason for this is because of the way that externally baffled ridge vents work and their use of the wind. Typically, the wind moves faster at higher elevations; therefore, the higher ridge will be exposed to higher wind speeds. If the wind speed difference is adequate, the lower static pressure at the higher ridge may be enough to draw air through the ridge vent on the lower ridge, which has slower wind speed and thus not as great of a low static pressure. This results in short-circuiting and possible weather infiltration. This rule does assume that the attic space is common to all the different height ridgelines. In situations like cathedral ceilings where each bay is separated, all ridges can be vented because no "attic space" is common to two different ridge heights. In some cases with joined attics, it is beneficial to physically separate the attic space into a few smaller attic spaces, each independent of the others. Using plywood or some plastic sheeting, you could create two separate attic spaces that are both easily handled with a ridge vent and intake vent system. The two spaces are now considered two attics, therefore, code applies to each separately and they must be vented for their specific square footage with a separate balanced system in each.