As of 0.9d the ‘Blizzard’ node in Summon Storm Totem does not work when selected as per Shaman, Level 100 (LE Beta 0.9.0i) - Last Epoch Build Planner. Enemies gain shock stacks and visually show lightning and stun visuals, as does the storm totem’s lightning attacks.
Storm totem is triggered via Spirit Thorns + Stormcarved Testament.
(Incidentally, if ‘overstimulation’ should produce Slow stacks, they are not currently visible on affected targets. This is true whether Blizzard is active or not. )