During geomagnetic storms, the rapid depletion of the high-energy (several MeV) outer radiation belt electrons is a result of loss to the interplanetary medium through the magnetopause, outward radial diffusion and loss to the atmosphere due to wave-particle interactions. We have performed a statistical study of 110 storms using pitch angle resolved electron flux measurement from the Van Allen Probes mission and found that inside of the radiation belt (L*=3-5) the number of storms that result in depletion electrons with equatorial pitch angle α=30 is higher than number of storms that result in depletion of electrons with equatorial pitch angle α=75. We conclude that this is an indication of electron scattering by electromagnetic ion cyclotron waves. At the outer edge of the radiation belt (L* >= 5.2) the number of storms that result in depletion is also large (~40-50%), supporting the significance of the magnetopause shadowing effect and outward radial transport.