If you're one of thousands of passengers grounded due to snow disruption, there are a couple of apps which could make life more enjoyable.

Guidebook publisher Lonely Planet announced December 21 that it is making 13 of its iPhone City Guides free until Thursday 23 December, to help travelers with things to do while stranded.

Guides included in the deal are Amsterdam, Berlin, Copenhagen, Dublin, London, Moscow, Munich, Paris, Prague, St Petersburg, Stockholm, Vienna and Warsaw.

The city guides also include details of hotels and restaurants, and Android users can download the publisher's Compass City Guides at a reduced rate of $0.99.

Travel comparison site TripAdvisor has also overhauled its app this week, bring new features for iPad users.

Mirroring the hugely-popular app from booking site Kayak, it has expanded the map to take advantage of the iPad's screen size, allowing users to view areas and drill down to the details on each listing from the map.

Critically, it allows users to search for locations close to them, view ratings and compare flight prices on the go, which could be vital for stranded passengers.

Finally, the popular app guide series Mtrip launched on Android for the first time last week.

It brings the trademark features of Mtrip guides, such as the Genius Trip planner, augmented reality and offline maps and directions, to twenty US, European and Asian destination apps available on the Google Android Market.