Page "Broach (sailing)" Paragraph 4

Another cause of broaching is encountered in heavy seas and high winds.

If the bow of the yacht is not kept pointed into the waves, then the waves will push the bow aside, turning the boat side-on to the waves.

Once side-on to the waves, the waves will roll the yacht side to side violently, causing severe discomfort to the crew, and the yacht may broach and may even capsize.

Since a sailing ship cannot steer unless the sails are providing forward motion, and since heavy seas are most often from the same direction as the wind, a sea anchor may be used at the bow in extreme weather to keep the bow pointed into the wind and waves.