There will be a slide-illustrated talk, with discussions and questions at 10am, repeated at 2pm and 6pm (the avalanche struck at 10.15am, 27 December 1836). The event is free. In memory and recognition of those who died and those who were made homeless you're invited to make a little contribution to Shelter, the charity for those rendered homeless.
Venue: The Snowdrop Inn, South Street, Lewes. The Snowdrop was built on the avalanche site itself. Best to park elsewhere (parking is not easy in South Street) and take a 10-minute walk through town: the Snowdrop is in square G3 on this map:
There's a short description of the disaster on the BBC website:
Other worthwhile places to explore on the Lewes 'avalanche trail': South Malling Parish Church (where the dead were buried and are commemorated with a marble plaque inside the building) ... and Anne of Cleves House, which has a small exhibit and painting of the avalanche rescue.
If you can make it, it'll be good to see you!