At dawn yesterday in the middle of a late season squall of rain and snow, more than 500 police and firemen set up a blockade around a six-block area of Powelton Village, a small, racially integrated neighborhood in west Philadelphia. The blockade is the city's biggest escalation in its 10-month siege of the headquarters of an anarchist organization known as MOVE.

Police - many wearing flak jackets under yellow slickers - permitted no one to cross the barricade, a 9-foot-high snow fence, except residents and their visitors - who were escorted to and from their destination.

Fire hoses and water cannons are trained on the MOVE headquarters, a run-down Victorian mansion with boarded-up windows and a high wooden fence around its large yard. Across the street police stood behind sandbagged windows of buildings.

Police sharpshooters were stationed on the roofs of nearby houses.

Within minutes after the blockade was set up an improvised armored truck covered with sandbags and flak jackets drove to the front of the building, and a policeman cut off the water supply to the house. Water was the last connection MOVE had with city services. Gas and electricity were cut off months ago.

The announced intention of the blockade, says Philadelphia Mayor Frank L. Rizzo, an ex-policeman with a well-established tough-cop reputation, is to starve out approximately 19 MOVE members who have been holed up in the building - along with up to 10 children and an estimated 50 dogs - since last May 20.

On that day, in response to an eviction notice, MOVE members appeared on the street in quasi-military uniforms carrying automatic weapons. Possession of nonlicensed automatic weapons is a federal offense, and the city has issued several warrants against MOVE members for violation of city weapons ordinances.

Rizzo says the police will not fire unless fired upon but if they are fired upon will respond with "more firepower than they've ever seen."

Police set up a 24-hour surveillance of the headquarters, arresting any MOVE member who left the house. The cost of the surveillance has been estimated at $1,217,000.

The court order permitting the blockade, issued by City Judge G. Fred DiBona, was granted for the purpose of permitting city inspectors to investigate the premises for violations of the sanitary code.

The confrontation, in which 25 to 30 human beings could starve to death or be killed by rifle fire, is the result of many factors: the intransigence of the MOVE organization, the reputation of the Philadelphia police force, the political career of Rizzo and the nature of Powelton Village, the neighborhood where all this is happening.

MOVE - members won't say what the apparent acronym stands for - was founded in 1972, apparently by Vincent Leaphart, a black handyman, and Donald Glassey, a white graduate of the University of Pennsylvania school of social studies.

All members take the last name Africa after their supposed founder, John Africa, who is possibly Leaphart and possibly fictitious. From its inception the group was committed to confrontation and to a primitivistic anti-technology philosophy.

Members refuse to cooperate in any way with government authority, and do not bathe with soap. Babies are delivered without medical assistance - the mother bites off the umbilical cord and licks the infant clean.Black members wear their hair in long dreadknots, like members of the Rasthfarians cult in Jamaica.

Most members do not eat cooked food, and all garbage is thrown into the yard of the headquarters to be "cycled" back to the earth. A large number of dogs contribute a large amount of excrement to the yard, and in summer, according to many neighbors, the stench is unbearable. Many rats have been attracted by the garbage, but MOVE refuses to kill them because they say to them all life is sacred.

Many of MOVE's first confrontations were with neighbors. Powelton Village is close to both the University of Pennsylvania and Drexel University. It was a center of antiwar activity during the Vietnam war.

Many Powelton residents have managed to hold onto the political principles of the time, though they have moved from the many student communes in the neighborhood to restored townhouses and tenure in the universities that they used to picket.

One group, the Powelton Emergency Human Rights Committee (PEHRC), all members of which have opposed Rizzo and the police in the past, now claims that MOVE members threatened to kill or castrate them and their children when they protested the lack of sanitary conditions in the house.

The lawyer for this group, Robert Guzzardi, who is not anti-Rizzo, says that the MOVE situation could never have happened anywhere else because only people in Powelton are so opposed to city authority that they could put up with MOVE's intimidation for years rather than ask help from Frank Rizzo.

Another group, Powelton United Neighbors, sees blockade and the continuing police presence in the neighborhood as part of the problem rather than a solution. Their lawyer, David Kairys, notes, "There's always somebody that tries to be brave and run the blockade - or pass in food - and it simply leads to an escalation of violence."

MOVE has carried its confrontation strategy to extraordinary extremes. It has threatened to "cycle or what society calls-kill, our own children" if city health inspectors or police force their way into the house, and its rhetorical style is rich in obscenities.

MOVE members, by their count, have been arrested more than 600 times in the past five years, mostly on misdemeanor charges. In court they refuse court-appointed lawyers, and engage in what judges call disruptive tactics.

Five members were sentenced to long terms for their part in a bizzare bomb plot. After a large amount of explosives was discovered and Glassey the co-founder-of-MOVE-turned-police-informer, said the organization, plans included obtaining an atomic bomb with which to threatened the city.

MOVE's philosophy has always included many contradictions. MOVE opposes technology, yet members use an electric bullhorn to harangue passersby, and for years the organization supported itself by washing cars.

MOVE believes it is necessary to restore garbage to the earth, yet keeps so many dogs at headquarters that nothing has ever been planted in the yard. MOVE claims to be nonviolent and respect all life, yet threatens neighbors and appears on the streets with guns.

City officials have pointed out that negotiations have proved to be impossible in the 10 months that MOVE members have been holed up in headquarters.

MOVE has insisted that its non-negotiable demands include a charter from President Carter guaranteeing their safety.

But by midday yesterday, with police everywhere and MOVE members in front of their house, whoever is using the bullhorn has slipped to a simple message: "F - all of Y'all! Long live John Africa! Long live Revolution!"