the accident yesterday

Are these sentences correct:
[color=indigo]1-The accident yesterday had no casualties.
2-I heard about the accident yesterday.

Is 2 ambiguous?
Can’t it mean:
[color=red]2a-Yesterday I heard about the accident. (Maybe the accident took place before yesterday)
[color=blue]2b-I head about the accident that took place yesterday. (Maybe I heard about it today)

Hi Navi,

I would change (1) to: There were no casualties in yesterday’s accident. In (2) you are right in saying that it could have two interpretations. For clarity you could say: I first heard about the accident yesterday or I heard about yesterdays’s accident.