The consequences of the March 1991 storm on the Earth's radiation environment are now well known through many in-situ magnetospheric observations. Measurement from the CRRES spacecraft show the sudden formation of a new Helium ion structure deep within the magnetosphere. In that event, two additional new radiation belts were created, one containing large fluxes of 10 MeV electrons, and the other forming a structure containing 30 MeV protons. These sudden space weather phenomena appear to be due the conjunction of the two occurrences: (1) a solar energetic particle (SEP) event arriving in the vicinity of the Earth, and (2) a very intense magnetic storm within the Earth's magnetosphere. Attempts to reproduce the appearance of storm time helium belt by computational modeling are made using a three-dimensional charged particle code (Salammbo code) incorporating Helium ion charge exchange and post-event classical diffusion theory. We have extended the capabilities of the code to Helium ions, and we show that these physical phenomena can also lead to a build-up of a new Helium belt in the 30 MeV range. Detailed modeling predictions of the location of this belt and computed flux levels will be presented and discussed in the context of space weather phenomena in the Earth's magnetosphere.