The frequency and severity of desert dust storms were observed at Burg el ''Arab, 3V2 miles inland from the Mediterranean shore line midway between Alexandria and El ''Alamein. This narrow semi-desert zone of moderate but erratic winter rainfall, intensely cultivated 2000 yrs. ago, is agriculturally unimportant. The land surface was subjected to mechanical disturbances incidental to military operations which culminated in the Battle of El ''Alamein (Oct.-Nov., 1942); a period of relative quiescence ensued. From an average of 3-4 dust storms per yr. the no. increased to 8 in 1939-40 (vegetation year Oct.-Sept.), 40 in 1940-41, 51 in 1941-42. Tank and truck travel, laying of mine-fields, making of airfields and roadways, influx of war-displaced Bedouins and their flocks, and subnormal rainfall of only 4 in./yr. combined to strip the perennial scrub cover, mainly Thymelaea hirsuta, and to pulverize the soil. Reserves of loose dust were thus immensely increased. 2 methods of estimating dust storm severity were used: weighing the dust which collected on unit area of a horizontal hard surface in a calm room during 1 hr., and count-ing the dust grains which fell in a circle of 1 mm. radius under low power (80x) of a microscope in a calm room. Maximum rate was 1/2 ton/acre/hr., while a more frequent rate was 1/6 to 1/8 ton/acre/hr. Horizontal visibility from a point 18 ft. above ground level was also used as a criterion of severity. Critical wind velocity was about 12 miles/hr. when the dust reservoir was relatively unlimited, but was much higher as the reservoir dissipated after 1942. Higher rainfall in winter 1942-43 (6.5 in.) produced good cover which inhibited dust storms. Seedlings germinating in early Jan. covered half of surface by Feb. and 3/4 of surface by the end of March. Dominants in this display of prostrate or trailing annuals were 3 spp. of Cruciferae; Carrichtera annua, Enar-throcarpus lyratus, and Matthiola humilis; associated were a composite Centaurea glomerata and a fenugreek Trigonella stellata. Light rainfall (4 in.) in winter 1943-44 resulted in sparse annual cover and a marked incidence of dust storms. Heavy rainfall (9.7 in.) in winter 1944-45 caused complete plant cover during the Khamsin season (March-May). Dust storms fell to nearly pre-war status. Gradual depletion of the war-caused dust reservoir and a slow hardening of the soil surface contributed to this trend, and subdued the intensity to a "sub-dust-storm" type. Perennial desert scrub cover showed continued rejuvenation after 1943, in which vigorous young plants of Thymalea hirsuta dominated.