Edmonton police are alarmed by a dramatic jump in the number of sexual assaults in the city.

Police say they don't know exactly why sexual assaults are up by 37 per cent this year, but suspect it may have to do with better reporting and drug and alcohol use.

"Both offenders and victims who are under the influence of alcohol," said Acting Chief David Korol. "We know other jurisdictions are experiencing the same thing as well."

Police presented the crime statistics at an Edmonton Police Commission meeting Thursday night.

There were 493 sexual assaults reported between January and September this year compared to 360 last year in the same period.

Police said of all sex assaults in 2009, victims had consumed liquor in in at least 40 per cent of them. A vast majority of those victims knew their attacker. In fact, police said, sexual assaults involving a stranger accounted for fewer than five per cent of last year's total.  

Police are now working with the Sexual Assault Centre of Edmonton on an education program targeting young people who frequent bars and clubs.

The program will consist of graphic ads on radio, televison and LRT stations targeting potential abusers.

But everybody has to play a role, said Korol.

"It's a message about looking after your friends," said Korol. "If you see one of your friends you go out with who has drank too much or under the influence, (make) sure you're there to assist that individual so that nothing bad happens to them."

Other crime numbers down

Police are just as mystified as to why, over all, crime in Edmonton is down by 18 per cent.

Robberies dropped by 25 per cent; vehicle thefts by 27 per cent.

Korol credits a more experienced police force, and the targeting of habitual offenders.

But criminologist Bill Pitt said there might be other factors such as an aging population - with fewer young people more likely to commit crimes.

He also suggests people are being more vigilant.