Use your low beams. The visibility in front of you will sharply decrease in a fog, so use the vehicle's low beam lights (if the vehicle does not have fog lights or driving lights). Heavy fog conditions prohibit use of high beam headlights. The light from high beam headlights will be reflected back by thick fog.
Largashbur, an Orc Stronghold. Orc Strongholds are scattered throughout Skyrim, High Rock, and Hammerfell. The Orcs have lived in Skyrim for centuries in tribal communities based around Strongholds. Orcs here live according to the rule of Malacath. Malacath, as Daedric Prince of the Orcs, is worshipped in these places.
The warehouse is located at the southern end of Riften's docks. Orini Dral is patrolling the warehouse, and will immediately spot you. Sarthis is in the basement and will come rushing upstairs to aid his bodyguard. Orini is a modest opponent, but Sarthis can prove a difficult opponent to defeat.