Hogwarts
Everyone in and around the castle would obviously be affected in some way by the rumble. The hardest hit would be the outside, on the school grounds. A few smaller trees would have their roots exposed, and a look of general mess would be around. Even from the Forbidden Forest, some rumors would come, indicating that the creatures within had also been disturbed.
As the tremor subsided, the few staffers who were already in the school started moving. The Hospital Wing staff - a nurse and, at the moment, only one assistant - left the place and started walking around the halls, searching for someone who could be wounded. While classes hadn't yet started, some students who didn't have families and staff members in the same situation used to spend their breaks still using the school as their main residence.
The nurse - a middle aged witch with a motherly manner - started roaming the halls to one side, directing the assistant to take the opposite way and look for anyone who might need help.
In Melony's office, the Headmistress would soon her knocks on the door and someone would open it timidly. It was the nurse's assistant, a young witch, still in training. "Excuse me, Headmistress... Is everything well here?", she asked, concern clear on her expression.
Diagon Alley/Leaky Cauldron
The Leaky Cauldron was getting fuller by the minute. People who were managing to reach the door were coming in, scared and disheveled. Comments crossed here and there.
"I lost my hat..."; "I don't like this..."; "Are you hurt...?". Questions and comments were plentiful, but answers weren't exactly available. As the place got fuller and fuller, a line was starting to form by the fireplace. It was clear many people had thought the same as Mrs. Umbrax - that the Floo network would be a reliable and safe way to travel at the moment.
In the hustle around, nobody seemed to notice the strange event with Rita's book. At least not while everyone was talking excitedly and trying to figure out what was going on.
While that happened, on the outside people were still trying to make sense of what was happening. And to protect themselves from that unnatural wind, while also trying to make sure their merchandise didn't get lost.
As the two professors and the grounds keeper planned on going to Hogwarts, a bunch of owls started flying into their alley, apparently having been freed from their cages by the wind.