I guess whoever pulled the data together didn't think to use Portland, but it's also high, (just below Miami-Dade). The 2022 point in time homeless count showed a total of 63 per 10,000 homeless, 26 per 10,000 sheltered and 37 per 10,000 unsheltered. There are roughly 6 people living unsheltered in Portland for every person counted unsheltered in Vancouver.
I think NE American cities have to shelter their homeless (given their winters, and summer heat). And of course our winter homeless count would probably be lower as the count is usually taken in May after our temporary cold weather shelters have closed.
One reason why our overall homeless count is comparatively modest, is because we have been building both permanent and temporary modular housing for welfare rate housing, which isn't the case in many cities. At one time Portland had a better record of housing their homeless population, but the growth in the number of homeless there has been more than their programs have been able to keep up with. It's grown from 2,000 unsheltered in 2019 to 3,000 this year.
Edit. We haven't needed to map our homeless camps
like Portland has since 2017