Marcus, though he knew going out in a hurricane was a dangerous proposition, wasn't completely prepared for the battering he got from the vicious weather. Nevertheless, with Tonks's spell and his cloak, he was able to protect himself from the worst of the storm's attacks. When Tonks linked her arm through his, he thought it a very sensible gesture. Didn't want them losing each other in the mess. After all, it was so nice to see each other after days of not.
Marcus watched Tonks do a trick with her wand, but wasn't sure what it was about. He attempted to ask her, but quickly realized the storm left no real verbal options. It was going to have to be hand signals and non-verbal communication, then. Too bad she didn't know any of the Ranger signals. He would have to teach her some, later.
After her wand break, Tonks seemed confident, and Marcus held her tightly in return as he let her choose the direction. She had chosen to go North along the beach, which he figured was as good a direction as any.