[en] The unusually large cosmic ray disturbance commencing on August 4 had three unusual features. First, a ground level event (GLE) was seen in neutron monitors at P/subc/approximately-less-than1.5 GV beginning at about 1400 UT, almost 8 hours after the large solar flare at 0630 UT. This GLE can be attributed to relativistic solar particles that experienced coronal spreading onto flux tubes coming out toward earth and had a rigidity spectrum for 0.7less than or equal toPless than or equal to2.0 GV given by 7times10⁴ P/sup -8.5plus-or-minus//sup 1//sup .0/ (m² s GV sr)^-1. Second, a large precursory increase was associated with the rapid Forbush decrease (Fd) at 2100-2200 UT. This precursory increase resulted from a free space anisotropy of approx.5% in magnitude, about 2 hours wide and in a direction 0degree-30degreeW of the E-S line. Third, the Fd had a short time scale, with an overshoot in the initial recovery phase. These rapid cosmic ray intensity changes are related to the interplanetary field changes and a model proposed for this rapid Fd