Arwel Jones, Director of Public Services at the National Library of Wales, told ITV News "our concern now is for the collection", and that it will take time for the extent of any damage to be estimated.
More top news
Tree pollen levels are easing off now! But beware - grass pollen is just becoming airborne and levels will rise during settled spells.
Northern areas will see a few showers this afternoon - but there'll be plenty of warm sunhine too!
Wales is facing a recruitment shortage for secondary school teachers. At the start of the year a third of training places were not filled.