The airlines do not control the weather but they should have contact details of pax to whom they sold tickets
At least they should have called and emailed around and told people they wil not be financially penalised so as to stop the influx

BBC NEWS Online
http://www.bbc.co.uk/news/uk-12034317
"Airport operator BAA said further cancellations and delays at Heathrow would be inevitable.

But many passengers were unhappy with their treatment.

Sarah Randall, from Hertfordshire, said she was stranded at the airport with her husband, parents and three children - aged six to 11 - after their Cathay Pacific flight to Hong Kong was cancelled on Saturday morning.

She said they slept on the floor on Saturday night and that her children were still traumatised by the experience.

She complained: "The weather was beyond their control, I know, but my gripe is the disgraceful way all passengers have been treated and abandoned."

She said the family is now back at home after her husband walked through the snow to flag down a taxi on the M4 slip road but they are yet to find out if the £16,000 cost of their "dream trip" to Hong Kong and Bali will be refunded. "