CHICAGO — WHEN sweltering 100-plus-degree weather struck the Midwest two weeks ago, Dora Clay felt her tiny apartment in a west Chicago public housing high-rise heat up like a kiln.
Fortunately, the home-bound nonagenarian found deliverance from the stifling heat with the help of a young woman, Sharon.
''My girl took me downstairs three nights in a row,'' says Miss Clay, who spent the evenings fanning herself in a chair outside the building. The community worker also kept electric fans running in Clay's bedroom and brought her water and iced tea.
As the crisis subsides and thunderstorms cool the region, experts ask why Clay coped well when more than 460 largely poor, elderly Chicagoans died in the heat wave. A critical underlying factor, they say, is isolation.
''It's not just physical isolation, but also social and political isolation,'' says Allan Schnaiberg, a sociology professor at Northwestern University in Evanston, Ill.
With the decline of welfare and traditional family ties, elderly people living alone in the inner city are increasingly cut off from both public and private sources of support, Professor Schnaiberg says. Many families that are scrambling to make ends meet have less time and money to care for aged relatives, he says.
Meanwhile, fear of crime keeps many of the elderly shut up indoors. ''The elderly are afraid of going out, of opening their windows and doors, of going to shelters. They are not just isolated, they are prisoners,'' he says.
In Chicago, which had more than half of the 760 heat-related fatalities across the country, a defensive Mayor Richard Daley last week announced new measures to help elderly citizens during future heat emergencies.
Under the plan, up to 150 volunteers manning a downtown Chicago phone bank would call some 300,000 elderly residents and assess their need for assistance. Police, social workers, meals-on-wheels drivers, and other city employees would monitor more closely the elderly who live alone. Residents would also be urged to check on older family members and neighbors.
''Government can't do it all. We need everyone to help if we're really going to make a difference,'' Mayor Daley said.
Daley also implemented a new, three-tiered heat-alert plan after he was criticized for Chicago's poor coordination of emergency care and failure to warn city residents about temperatures that soared to 106 degrees F on July 13.
In other measures, Chicago will receive $6 million in federal aid to help poor residents buy fans and air conditioners. The money is part of a $100 million emergency package President Clinton announced on July 21 for the 19 states hit hardest by recent heat waves.
Illinois is granting the city another $250,000 to subsidize the utility bills of low-income residents. And state Rep. James Durkin proposed legislation aimed at guaranteeing electricity to low-income residents during extremely hot weather, even if they haven't paid their bills. The law would prohibit utility companies from cutting off electricity on any day when the National Weather Service forecasts temperatures of 90 degrees or higher.
While welcoming the latest aid and emergency plans, some experts say they believe that the city should devote more resources to long-term efforts to alleviate the isolation of senior citizens. Especially important to preventing future tragedies, they say, is expanding the programs of neighborhood- and community-based groups that regularly check on seniors.
Clay, who has no children and lives alone on $647 a month, is one of 750 elderly who benefit from visits by home-care workers from the Bethel New Life community group on Chicago's West Side. Each of the group's 200 workers spends an average of three hours, three days a week cooking, cleaning, and providing other help and companionship for elderly people in the community.
''The alternative to providing this kind of preventative care now is really catastrophic,'' says Hassan Muhammad, director of senior services for the nonprofit, church-based group. Still, he said in recent years a lack of state and private funding has forced several Chicago-area agencies to discontinue their services to the elderly.
Clay says the daily knock on the door and visit from Sharon has been a godsend, especially during the oppressive heat.
''I could never have done it by myself,'' she says. ''I've got to have somebody.''