County should have levelled through Ludovic Dje while Chris Lumsdon hit the post for Carlisle, but the floodgates soon opened. Flying winger Simon Hackney crossed to Hawley who flicked on and Holmes couldn't miss from two yards out.
Ninety seconds later came the third when County keeper Carl Ikeme punched a Paul Arnison into his own net. With Brunton Park bouncing Ikeme made another howler just four minutes later when his poor goal kick fell straight to Raphael Nade. The former Woking winger jinked past two defenders and crossed for Holmes to power a volley into the top corner.
Despite the game being all but over, Carlisle still pressed forward and could easily have had another four goals in the 2nd half.
With Ikeme producing a torrid performance and seemingly uninterested in coming for any crosses, it was no surprise that Carlisle hit almost everyone of their 11 corners under his crossbar.
Lumsdon, Hackney and Nade all went close to making it five before Hawley grabbed his second, nodding in from under the bar from another Lumsdon corner.
With both strikers sensing a treble, Paul Simpson took off the unlucky Holmes and brought on Glenn Murray, to terrorise the visitors defence further.
Murray's influence was immediate, and with his first touch, he robbed a defender and squared for Hawley to slide in and grab his ninth goal of the season. Murray himself could have scored late on, but Ikeme saved well with his foot.
The Cumbrians were cheered off the pitch after a win that takes them up to sixth in the table.