Meanings of improbably long in English

It burned and it burned, with improbably long crimson flames, and gave off a whirl of thick black smoke.

At 500ft, it looks like a Yann Arthus-Bertrand photograph; the fields make abstract patterns and trees cast improbably long shadows.

Not so for the Miura, which somehow disguises its everything-in-the-middle powertrain with an improbably long hood, an impossibly low stance and a delicately tapered deck.