"...the debris was big: a piece of an unmanned Russian rocket, 10 square metres in size."
"The rocket had blasted off from Kazakhstan on Tuesday and carried materials for the International Space Station. And when it re-entered the Earth's atmosphere, things got a little scary for the province of Alberta."
"NORAD called the federal government at 10:15 a.m. on Friday morning to let them know about the falling debris, and by 10:30 a.m. the Alberta Emergency Management Agency (AEMA) had been notified. The time of impact was estimated to be 10:46 a.m."(link)
The government of Alberta was given 16 minutes total of warning. Wait! Where's the premier of Alberta jumping up and down in hysterics over his oil getting bombarded like Danny Millions did in 2005?
Because it's simple: the chances of a 10 meter^2 sized piece of debris firstly making it through the atmosphere without breaking up, and then secondly to hit a sensitive area are so remote you would be better on betting on lotto 649.
Let's do some extremely rough math here (statisticians please hold your nose):
The province of Alberta has a land area of over 600,000 km^2. Assuming that 10 m^2 piece of debris makes it to the ground intact that works out to a 1 in 60 billion chance that any one 10 m^2 location will be hit. If you assume that they knew for sure that the city of Calgary would be hit the chances of any one spot getting hit increases to something like 1 in 70 million.
If you assume that every square kilometer of Albertan land area has a 250000 meter squared zone that is vulnerable that works to odds of 1 in 2.4 million that a sensitive zone in Alberta will be struck.
I admit these are "rough" numbers but they illustrate my point. The odds are incredibly low.
If you don't believe these numbers see for yourself what the Center for Orbital and Reentry Debris Research has to say:
"Reportedly, only one person has been struck by debris from a reentering satellite in the history of our use of space. Fortunately, this person was hit by a lightweight object and was not injured."
"The risk that an individual will be hit and injured is estimated to be less than one in one trillion. To put this into context, the risk that an individual in the U.S. will be struck by lightning is about one in 1.4 million."(link)
It seems that my earlier estimate was (gulp!) fairly liberal.