If you're outside and fall for 10 seconds at 1g, that's 500 metres, so anyone outside would fly 500 metres into the sky then plummet to their deaths when gravity resumed (you'd be doing about 100 m/s at impact). Anyone indoors e.g. in bed or in a chair would fall face/head first into the ceiling. Then 10 seconds later, you slam back to the floor. People in cars with seatbelts would be the safest, however it's likely that many car accidents (etc) would occur and fires etc would break out (because of people dropping cigarettes, and otherwise knocking fire-starting things over. There wouldn't be enough hospital staff left to cope with close to 100% of the population being injured to some degree, so i'd imagine disease would break out too.
So the first year it would depopulate large chunks of the Earth. People would rebuild, but ... on the second year it's unlikely that anyone is expecting it to happen at exactly that time, and so much of society would be devastated that perhaps they aren't prepared for it. The population would dwindle over several years but eventually people would work it out and I'd imagine life would be a lot like before, but with extra precautions around that time of year.
And I imagine some form of religious belief or cult would form around the incident, perhaps heretics / criminals would be left outdoors at that time of year as a form of execution.
Another possibility would be to turn it into a sport / thrillride. Wear a parachute and wait for the lift, then pull the chord and sail back down.