Boston — If Soviet cities began emptying during an international crisis, wreckers and signs would mark US highway evacuation routes, and, hours later, the President of the United States would announce a nuclear emergency. Then Sandy Zeamer is supposed to leave her apartment in the Beacon Hill section of Boston and head for Litchfield, Maine.
Litchfield postmaster and civil defense chief Rudolph Landry says he hopes she brings a tent.
Ms. Zeamer's posting to the Maine woods mirrors federal plans to move 150 million people - two-thirds the US population - from 400 high-risk areas to 2, 000 host areas if a nuclear attack appears imminent. As part of the Reagan administration's planned $4.2 billion, seven-year civil defense buildup, each state is working on plans to evacuate people from cities, military bases, and strategic industries if nuclear war looms.
Massachusetts is ''ahead of most states in planning'' for evacuation if a nuclear attack threatens, says Doug Forbes, chief planner of the Massachusetts Civil Defense Agency. The state is marking individual shelters and expects to be stocking them over the next six or seven years. But the towns of Amherst, Acton, Cambridge, Newton, and Northampton have said they will not cooperate with state planning.
They join Arlington, Va., Boulder, Colo., Greensboro, N.C., Houston, Little Rock, Ark., Marin County, Calif., New York, Philadelphia, Sacramento, Calif., St. Alban's, Vt., and Woodstock, Vt., which all have rejected federal civil defense plans.
Recently, the Boston City Council held a stormy daylong public hearing on evacuation plans for the city.
Litchfield's summer camps along its seven lakes might prove its ''biggest resource'' during an evacuation, Mr. Landry says. But while striving to cooperate with federal plans, he points out that Litchfield itself ''might need to evacuate'' since it is within the evacuation zone of the Maine Yankee nuclear power plant.
The Federal Emergency Management Agency (FEMA), charged with overseeing evacuation in the likelihood of nuclear attack, is undeterred by growing public doubts about the merits such planning. At FEMA's request, the Gallup Organization is conducting a poll of Americans' knowledge and opinion of civil defense.
While planners determine how much earth would need to be shoveled against buildings, or how 1,500 cars per lane per hour could begin their trip using all six lanes of the Massachusetts Turnpike, President Reagan seeks to boost civil defense spending to $252 million next year from $133 million requested this year. The administration also wants to increase the number of federally-paid civil defense planners from the current 200 to 485 next year.
''Unwise and futile, quite impractical'' is how John Steinbruner, director of foreign policy studies at the Brookings Institution, describes such a civil defense push. ''As long as you are in the continental US, there is nowhere you can go to be really be safe'' during a nuclear war, says Mr. Steinbruner, an expert on strategic nuclear policy.
US planning assumes that any nuclear attack would be preceded by weeks of rising international tension and that the USSR has extensive civil defense plans.
Intercontinental ballistic missiles (ICBMs) launched from the Soviet Union could reach US targets in half an hour. But civil defense officials say a period of deteriorating international relations would allow adequate evacuation time. They say all but three US ''risk'' areas - New York, Los Angeles, and San Francisco/Oakland - could be evacuated in three days or less, while it would take three to seven days to evacuate all Soviet cities.
Forbes says the USSR ''absolutely'' would evacuate its people because ''its industry is much more labor intensive (than in the US) so people are much more important.''
Steinbruner says of Soviet manuals that mention moving people out of cities, there are ''reasons to be skeptical about how seriously they should be taken as a reflection'' of Soviet leaders' planning. Soviet officials ''like to have control over where people travel'' and are unlikely to alter that policy during a crisis, he says. Steinbruner also says that during nine months of the year, harsh weather in the Soviet Union would render it impossible to feed and sustain evacuees.
But FEMA planners are confident ''crisis relocation'' in the US could proceed with less congestion than a weekday rush hour entails. ''We do a mass evacuation twice a day,'' Forbes says.
If a US president decided to evacuate probable targets of a nuclear attack, state and local governments would be notified. Federal plans allow six hours for wreckers and law enforcement personnel to reach their stations along posted evacuation routes. Then the President would announce a ''crisis relocation'' over the National Attack Warning System on TV and radio.
Boston is divided into 18 sections for evacuation, with evacuees proceeding to Maine along 10 routes. The 220,000 Bostonians - 40 percent of the city's residents - who don't have cars will be evacuated on trains and buses appropriated from public and private fleets. Buses will ''probably not go until after the bulk of the traffic'' is on its way, says Forbes.
In Maine, a state that every summer greets visiting hordes with a steely smile, the news that 65,000 evacuees from Boston's Allston-Brighton section would be destined for Waldo County left the county's residents ''appalled,'' according to civil defense officer Bill Worth. The rural county is assigned evacuees that number more than twice its population. Mr. Worth says people in Belfast and surrounding towns ''didn't know where they were going to put them.'' In the Maine shelters prepared for ''congregate care,'' each evacuee will have 20 square feet.
So far, planners have not decided how long Americans would need to remain at their new addresses.
''Two or three weeks'' is the length of stay FEMA planners use as a guide, according to public affairs officer Dave Denne. The advisability of letting people come and go would be left to state and local governments, he says.
By evacuating strategic areas, the US will have ''bought time for further negotiation'' Forbes says. But Brookings's Steinbruner sees a conflict. While saying it is ''extremely difficult to imagine how a nuclear war might begin,'' he says both sides might make ''several runs back and forth'' and he foresees ''pressure during a lull'' to allow people to return home. Yet a government might want to ''sit them there while they negotiate.''
But FEMA's Denne says civil defense planning is ''worth doing because it's better being away from ground zero than at ground zero'' and that while ''150 million lives could be lost, 100 million might survive.''
A recently disclosed Pentagon strategy for a protracted nuclear war has not altered FEMA's civil defense plans.
''The strongest human instinct is survival,'' Denne says, and even those who now say there will be no place to hide will ''jump in their cars'' if nuclear war looms.