“Mist muged on þe mor malt on þe mountez
Uch hille hade a hatte a myst hakel huge”
The moor was muggy with mist, and the snow melted on the mountains,
and each hill had a mantle of fog
So “myst-hakel” means literally a ‘mist-hood’ or ‘mist-cape’, fog that cloaks the earth. An apt description for the mist that shrouded Coate Moor this morning.