Montgomery County Board of Education President Blair Ewing said last night that the school system would face a severe crisis if two high schools in the lower Silver Spring area are allowed to remain open.

Ewing made his comments during a discussion by the board about whether it should reconsider reopening or delaying the closing of Northwood and/or Peary high schools, both scheduled to close in June 1984.

Board member Odessa Shannon was absent last night, and when it became apparent the remaining six board members were deadlocked on the question, the board voted to take up the matter again Thursday night, when Shannon is expected to be present.

Ewing told the board that any reopenings or substantial delay in the closings would cause serious funding problems and have a severe impact on racial balance at Montgomery Blair High School in Silver Spring, a school with a high minority enrollment. School officials estimate that it costs about $1 million a year to keep a high school open.

The State Board of Education, in an unprecedented move, last summer rejected a boundary change by the previous board for the Blair area that did not reduce the minority enrollment there. The state board ordered the local board to submit a new plan providing for a large enough enrollment at Blair to reduce the minority percentage and allow the school to offer a diverse program of study.

In particular, Ewing said that if Northwood remained open, Blair would lose some white students from that school scheduled to enroll at Blair. Blair has a minority enrollment greater than 60 percent; the county average is 25.4 percent minority school enrollment. Other board members argued that under one plan before the board, suggested by board member Robert Shoenberg, minority enrollment at Blair could be reduced while at the same time Northwood could remain open. This plan calls for placing a math-science "magnet" program at Blair and a government training program at Northwood.

Ewing disagreed with the projections and said that without substantial boundary changes and large numbers of students, "magnet" programs, which are supposed to reduce minority enrollment by bringing white students into a school from outside the boundary, have not succeeded.

In addition on Thursday night, the board will consider other boundary changes for elementary schools in the Blair area.