On the CBC last night they showed a picture of the Flames arena, and said that with the flood the first 14 rows of seats would be under water...don't think the Stamps stadium would fair much better....
McMahon stadium is in the NW part of the city, near the University of Calgary. As with the upcoming Stampede, I am sure the CFL Stamps will be playing their scheduled games. It will help the city recover.
The federal Conservative Party has delayed their July convention until the autumn, because they were scheduled downtown, which was heavily flooded.
Historically speaking, Depressions and tragic events actually result in an increase on entertainment spending (sports, movies etc) as a form of cathartic escapism, thus the Stamps may have a turnstile improvement this season.
A good showing by the Stamps could invariably help boost City morale similar to the Bruins in Boston most recently.
Structurally, Calgary will rebuild, although the loss of lives is irrecoverable and heartbreaking.
I can see the cathartic escapism happening with a single tragic event but long term economic depression is a different story. That’s currently happening in some European countries with extremely high unemployment. The people simply do not have the cash to pay for big ticket sporting events and as a result many European soccer clubs are playing to only a couple of thousand people in a 30000 seat stadium.
Calgary as a whole is quite affluent though so hopefully your suggestion about a spike in attendance is right.
The question isn't whether residents would want to go to the game - I think you're right that people will want something other than the flood to think about, even for a short time. The question is whether the city's infrastructure - roads, bridges, C-Train, hotels - will be ready in time. If the downtown hotels aren't open yet, will there be enough rooms for out-of-towners to stay? If the C-Train tracks haven't been repaired, will people in the south and north-east be able to get to the game, assuming not all will want to drive? When will the bridges be inspected for damage, and if any damage is discovered, how long will they be closed?