Ballot boxes are flown to Lewis from other parts of the Western Isles
An islands council is monitoring restrictions on flights in the run up to the count of general election ballot papers on Thursday.
Ballot boxes on Barra and the Uists are usually flown by helicopter to the Western Isles' count in Stornoway on Lewis.
Comhairle nan Eilean Siar said they would be delivered by sea and road if volcanic ash prevented flights.
The authority said this would delay the election result until midday on Friday.
Flights in Scottish airspace have been disrupted since the weekend.