The attic is making noises loud sharpe noises. It happen about 11:00pm and again 7:30 & 8:00am. I noticed the raffters are bowwing. It is hard to tell how much. Also my vent for plumbing, a pvc pipe going through the roof is off center it is toward the top off the roof line and toward the bottom there is a small gap where you can see day light.
The weather went from the 30's to -6 degrees. Would this have anything to do with the noise.

If the rafters and vent weren't bowing before... then you better get someone who knows what they are doing to do an emergency inspection of your home.

I think the raffters were bowing before because I remember seeing the gap in the vent last fall.

OK... then its not something that suddenly happened... that changes the urgency a great deal.

With a sudden and sharp change in temprature you can and many cases do get a number of sounds front he house as things expand or contract at different rates. The more rapid the change the more and louder the sounds may be.

Thanks smoothy

I will keep an eye on the raffters make sure they are not moving. Maybe I can rig up something to measure any movement. Thanks again.

If things are moving you should see it reflected in the drywall or plaster of the walls or ceiling. They are not all that flexible and will crack or crumble. Assuming its not a manufactured house that may use different materials.