Electrotransport in thin Al strips was directly observed by transmission electron microscopy. As expected, hole formation was seen in regions where the electron flow was in the direction of increasing temperature. Hillocks and whiskers were seen to form where the electron flow was in the direction of decreasing temperature. Cine´ films taken of the process show the holes to grow predominantly by a transverse movement of narrow fingers which ultimately coalesce and lead to a catastrophic strip burn‐out.