Il faut lire en fait "Holsom", c'est une coquille dans le dossier SHD/MDH de Leprou.
Voici ce que j'ai trouvé :
No. 34 Service Flying Training School:
Originally a dirt airstrip that opened in 1912 outside Medicine Hat, the Royal Air Force assumed control of the aerodrome and opened a flying
school on 8 April 1941, part of the British Commonwealth Air Training Plan.
The school also had Relief Landing Fields along the Holsom County Road (paved runways) & in the District of Whitla (grass runways). The RCAF
would later take control of the school.
The school closed on 17 November 1944, as did RCAF Detachments Holsom & Whitla.
The aerodrome was transferred to the Town of Medicine Hat in 1947 and is now the Medicine Hat Municipal Airport. Only two of the original six
runways remain in use, one expanded to 5000 ft.
The former fire hall, now used as a meeting hall, also remains, along with one hangar pad and the old German Merchant Navy prisoner of war
barracks with their old tar paper covered outer walls and some German graffiti on the inside walls.
A monument was erected at the airport as a tribute to the men and women who served at the wartime school.
Nothing remains of RCAF Detachment Whitla, which was returned to farming.
RCAF Detachment Holsom’s runway was ploughed under for farming as well, but a few chunks of asphalt can still be seen.
Source : https://militarybruce.com/abandoned-canadian-military-bases/abandoned-bases/alberta/