Snape's part in death of Sirius

[potioncat]

No: HPFGUIDX 107774

 
> Neri:
snip
> Slightly irresponsible, IMO, especially if we remember the level 
of 
> security that the Order had kept around Harry in the beginning of 
the 
> year. Two students went with the furious Umbridge into the 
dangerous 
> Forbidden Forest, and Snape just sits and waits two hours for them 
to 
> return? 


Potioncat:
Where does the 2 hours come from? Do we know how much time passed 
between Snape discovering Harry was gone and his notifying the Order?

Neri:
 > Allow me to guess that any other member of the Order, in Snape's 
> place, whould have grabbed a broom immediately after checking on 
> Sirius in HQ, put a dissillusment spell on himself and went after 
> Umbridge, Harry and Hermione. If Ron and the rest could track 
Harry 
> in the middle of the forest on foot, Snape on a broom could have 
> found them much faster.

Potioncat:
I am assuming, whatever the time, that the kids had left the forest 
by the time Snape is looking there.  Do we know "when" he found out 
that anyone had left the castle?


Neri: 
> DD maybe trusts Snape, but he should not trust him to act 
responsibly > whenever Harry is involved.

Potioncat:
This could be a fun, meaty  thread to debate, but I do have one 
major question.  With all the errors we've made with Mark Evans and 
the HBP: Is it your thought that JKR is showing us that Snape 
delayed looking for Harry?  
> 
Potioncat who admits she wasn't able to check canon before jumping 
in.