The March 1998 storm was chosen as an example of a high-speed solar wind-driven storm. It can be contrasted with the June 1998 and May 1997 storms which were driven by a classic-looking interplanetary magnetic cloud. All three were similar in ring current intensity (as measured by peak Dst) but the main phase of the June 1998 storm was significantly shorter and the relativistic electron fluxes were significantly less intense than for either the March 1998 or June 1998 storms.
Description of IMF conditions from Vania Jordonova
A stream-stream interaction region observed by the WIND spacecraft
from 12 UT to 24 UT, March 10, 1998, triggered off a major magnetic
storm which peaked within few hours at Dst=-126 nT and Kp=7+.
During this main phase of the storm the North-South component
of the IMF was large and negative (-15 nT). The interplanetary
medium on March 10 is further characterized by the following features:
a high dynamic pressure of ~8 nPa, a low proton $\beta$~0.3, a
low Alfven Mach number of ~5, and a high Pointing flux into the
magnetosphere of ~0.08 mW/m2. Thereafter, a 5-day Alfven wave
train on the faster stream in which Bz fluctuated about zero with
a peak-to-peak amplitude of ~6 nT lead to lower level activity
with an average Dst=-50 nT, after which a recovery takes place.