Seize the Storm

You must still follow any timing restrictions and permissions, including those based on the card's type. For instance, you can cast a sorcery using flashback only when you could normally cast a sorcery.

While a spell is on the stack, it is neither in your graveyard nor in exile, so it won't contribute to the Elemental's power and toughness. For example, with Seize the Storm in your graveyard and no cards in exile, the 1/1 Elemental in the above scenario will become 0/0 and die if you cast Seize the Storm from your graveyard using flashback.

The power and toughness of the Elemental token will change as the number of instant and sorcery cards in your graveyard and the number of cards with flashback you own in exile change.