Clamber

clamber \KLAM-buhr; KLAM-uhr\, intransitive verb:
1. To climb with difficulty, or on all fours; to scramble.

noun:
1. The act of clambering.

He dithered for a moment, during which time Mrs Hardy, wailing like a banshee, rushed from the dining room and clambered clumsily up the stairs.
-- Beryl Bainbridge, Master Georgie