The M4 Second Severn Crossing and the M48 Severn Bridge were closed last Friday and Saturday and again on Monday night, after sheets of ice dropped onto cars damaging windscreens. "On the [four lane] M48, ice formed on the suspension cables and on the [six lane] M4 ice formed on the cable stays and on the sign gantries," said Severn River Crossing general manager Jim Clune.
The Highways Agency dismissed the incident as unprecedented. "The cables do not cross the carriageway and normally any ice formed would fall directly downwards," said an Agency spokesman. "However, in this case the wind was blowing across the bridge and the ice fell into the road. We are now looking into what happened and talking to engineers on other bridges to see if they have ever had such problems."
Bridge engineers contacted by NCE said that the problems experienced on the Severn crossings were unusual and doubted that any measures should be taken on UK bridges as a result. "We don’t design for this [ice formation] in the UK as it is a rare event and would require a protective shield of rather substantial proportions," said Flint & Neill chief executive officer David Mackenzie.