Wadi Esfai is a seasonal watercourse in the Hajar Mountains of Ras Al Khaimah, United Arab Emirates.

Wadi Esfai receives high levels of winter rainfall, sufficient to trigger flash floods powerful enough to wash away the road traversing the wadi[1] and will also receive rainfall in the summer months.

[5] Meharia philbyi was named for the Arabist and explorer Harry St John Philby in 1952.

The new moth was named for its discoverer, German entomologist Roland Breithaupt.

[4] A 1937 survey of wadis in Southeastern Arabia undertaken by the British Air Ministry found Wadi Esfai to be a 'valley of small villages of Mazari, acknowledging the Sheikh of Sharjah', an allegiance that appears to have changed in subsequent years.