In a statement to the BBC, police said the search strategy is under review and that all new searches are subject to weather conditions, availability of resources and operational commitments.
It turns out that the smart grid will also enable solutions to the complex operational challenges associated with many industrial applications under extreme conditions.
Heathrow Airport said it was fully operational but some disruption was expected because of weather conditions at other airports in the UK and across Europe.
The directive must codify who can divulge what, when and under which conditions, and call for a universal commitment to accurate reports that also maintain operational security.
Lord Adonis said that in the face of "the most prolonged spell of freezing conditions" in the country since December 1981 "all main transport networks are operational".