[Update: I originally believed this showed the 1937 typhoon, but as you'll see in the comments below, it actually shows the after-effects of a 1936 typhoon]
When: The big typhoon of 1937 hit Hong Kong early morning on September 2nd.
"Several gusts exceeded 125 m.p.h., and it seems probable that the typhoon was the most violent which has ever visited the Colony." 
Things have settled down by the time this photo was taken, likely the following day.
Who: The spectacle has attracted a crowd of onlookers, no doubt relieved to have survived the typhoon unhurt. Many of those living at sea weren't so lucky - initial estimates said 11,000 "in native craft" were killed . Thankfully the final figure was much lower, but still recorded 2,565 deaths.
Of the people we can see, my favourite is the young boy at the bow of the boat. He's wondering whether one sharp push would be enough to send it back into the sea:
What: Can anyone identify the ship?
It has a couple of distinguishing features; a gun on the front deck:
and these two Chinese characters above the bridge:
Are they "海鶖", a type of sea bird ?
Could it be a Chinese Maritimes Customs cruiser? An article in the newspapers , said one was washed ashore:
Along the foreshore at Laichikok were a large number of junks and several small launches washed up on the shore beside a Chinese Maritime Customs cruiser and a river steamer.
Where: The tide has gone right out, leaving wet sand in the background, so it's somewhere with shallow water. The ridge in the background looks like the hills at the back of Kowloon.
Do they match the area around Lai Chi Kok?
Please leave a comment below if you can tell us more.
Trivia: Whoops! The 1st September newspaper  had an article titled:
Typhoon will miss H.K.
The next day's paper  found some good news among the death & destruction:
Catching Fish in Nathan Road
Following the flooding of the railway track, enterprising Chinese were seen "fishing" in pools of water in Nathan Road, many catches of still live fish being obtained.
Among them was one several feet long, of a breed unfamiliar to Hong kong waters, which had evidently been swept along by the typhoon for many miles.
- The Royal Observatory's report for 1937 : "The destructive typhoon of September 2nd. The typhoon passed close to the south side of Hong Kong Island on a WNW track between 3 and 4 a.m. At the Observatory the minimum barometer reading, reduced to sea level, was 29.298 inches, which is the lowest recorded since observations commenced in 1894. Several gusts exceeded 125 m.p.h., and it seems probable that the typhoon was the most violent which has ever visited the Colony."
- The Harbour Master's report for 1937 : "The loss of life in native craft was at first estimated at about 11,000, but is now reported to be 2,565."
- Hong Kong Sunday Herald, 1937-09-02, page 1.
- Hong Kong Sunday Herald, 1937-09-01, page 1.
- The China Mail, 1937-09-02, page 1.