PORTLAND – The number of women seeking shelter appears to have spiked upward, and officials are trying to figure out why.

A Point-In-Time survey of homelessness on April 26 showed Portland shelters had 156 men and 111 women. There were only 53 women in shelters during the same survey a year earlier, officials said.

Furthermore, women accounted for the entire increase in the adult shelter population at the time of the surveys.

City, state and federal officials were at a loss to explain the survey results, and it remains unclear whether the larger number of homeless women was part of a trend or simply a statistical anomaly.

Gerald Cayer, director of Portland’s Health and Human Services Department, says understanding why the number of women seeking emergency shelter has surged is key to helping them find permanent housing.

“Domestic violence and substance abuse are indicators there [for women],” he said, although that does not necessarily explain the significant increase.

There were 337 people staying in Portland shelters when the survey was taken this spring, up from 232 in 2003 and 192 the year before, though in each case, not every homeless person participated in the survey.

The city routinely must employ its overflow plan because the 154-bed Oxford Street Shelter cannot keep up with demand by single adults, Cayer says.

That increase comes with a cost, both financial and human. The city, state and federal governments spend $7.5 million on city-administered programs for the homeless and that spending is complemented by the work of local nonprofit groups. Still, three homeless men were found dead outside last winter.

Much of this year’s increase is attributable to the 48 children in the city’s family shelter compared to 24 the year before. There were 58 additional women in shelters who participated in the survey.

The number of women staying at the Oxford Street Shelter continues to be a small percentage compared to men, but women also were seeking shelter at the YWCA, the city’s family shelter and shelters especially for women in mental health crisis or escaping an abusive relationship.

Thirty-nine women reported that they had been the victim of domestic violence, with more than half saying the violence drove them from their homes.

More than 50 percent of homeless women reported having a chronic substance abuse problem, such as alcoholism or drug addiction, and three-quarters said they had serious mental illness. Similar issues contribute to male homelessness, with 103 of the 156 adult men reporting chronic substance abuse and half saying they had serious mental illness.

Historically, the number of homeless men has far exceeded the number of women, and that continues to be borne out at the state level.