VANCOUVER, British Columbia — She has passed her days painting flowers, conferring with her lawyers, reading books and improving her English, ensconced in two different multimillion-dollar mansions in exclusive sections of Vancouver.

But on Friday, after the city experienced a rare snowstorm, Meng Wanzhou, the Huawei chief financial officer detained in Vancouver and awaiting an extradition hearing on fraud charges, could be seen playfully throwing a snowball outside her house.

Then she spotted a photographer. Her smile turned into a frown.

In the 13 months since Ms. Meng, 47, was arrested at the Vancouver airport, her life has been circumscribed by the terms of her $10 million bail. On Monday, it entered a new phase when her extradition hearing formally began.

This part of the hearing, which could last a week, will examine whether the crime Ms. Meng is accused of constitutes a crime in Canada, a prerequisite under Canadian law for her extradition to proceed. This is known as the legal concept of “double criminality.”