Interesting, no definition in Section 30 of the Wildlife Act in Alberta for example on impairment level [as in Section 253(1) of the Criminal Code, Operation while impaired]. The individual could still be impaired the next morning when setting out but depends on how long the effects last for that individual.
How Long Do Marijuana Effects Last?
Effects of smoking marijuana are noticeable within minutes after the first toke, and usually reach peak levels after 30 minutes. Most physical and psychological effects of marijuana will return to normal within 5 hours after administration, with exceptional strains or high potency THC effects reported to last for 24 hours.
http://drug.addictionblog.org/how-long-does-marijuana-last/
Alberta Wildlife Act
Alcohol and drugs
30 A person shall not hunt wildlife while the person’s ability to
hunt is impaired by alcohol or a drug.
http://www.qp.alberta.ca/documents/Acts/W10.pdf
http://laws-lois.justice.gc.ca/eng/acts/C-46/section-253.html
How Long Do Marijuana Effects Last?
Effects of smoking marijuana are noticeable within minutes after the first toke, and usually reach peak levels after 30 minutes. Most physical and psychological effects of marijuana will return to normal within 5 hours after administration, with exceptional strains or high potency THC effects reported to last for 24 hours.
http://drug.addictionblog.org/how-long-does-marijuana-last/
Alberta Wildlife Act
Alcohol and drugs
30 A person shall not hunt wildlife while the person’s ability to
hunt is impaired by alcohol or a drug.
http://www.qp.alberta.ca/documents/Acts/W10.pdf
http://laws-lois.justice.gc.ca/eng/acts/C-46/section-253.html