As was reported earlier in the live snowstorm blog, the Yerushalayim eruv is down. The Eruv Vaad is working to complete repairs but as of now, the eruv is down.

YWN-ISRAEL spoke with a representative of the Badatz Eida Chareidis Eruv Vaad, and he reports the eruv is down.

Rabbi Yissocher Dov Krakowski provides a review of the halachos including the need for many to make an eruv charzeiros.

Following is Rabbi Krakowski’s instructions: 
Whenever the weather causes trees to fall one has to assume that the local Eiruv is down. Since the Eiruv isn’t stronger than trees or power lines we cannot assume that the Eiruv will withstand a natural disaster that the former wouldn’t.
Many of us living in cities like Yerushalayim are not used to not having an Eiruv and there may be certain points that are important to take into account. The following is a list of some of the important things to keep in mind:

If there isn’t an Eiruv in your neighborhood you cannot carry outside of your apartment if you live in an apartment building (or similar). One can however make an Eiruv Chatzeiros in their building which would permit everyone in the building to carry throughout the building (see instructions at the end of sheet).

One may not wear a hat cover (or sheitel cover) if its purpose is to protect your hat/sheitel. If you are wearing a cover on top of your Sheitel/hat but you are doing so because your sheitel/hat won’t keep YOU dry then it is permissible to do so.

If you generally carry a key on Shabbos make sure to make another arrangement for opening the door on Shabbos.

It is best not to go out with little kids on Shabbos as you cannot carry them if they cannot walk (suddenly while out). If you go out with a child and while out the child cannot continue to walk it is best to carry the child together with another adult. If you get stuck alone outside with a child who can no longer walk it is best that the child climbs on your back (piggy back style). The child can hold on to you but you should not hold on to the child (if possible without causing danger).
Make sure to check your pockets for loose items before going outside.

In order to make an Eiruv chatzeiros:
If you are making an Eiruv for a small building where there are fewer than 18 people (households) then you only need a minimal amount of bread per person if there is more than 18 households you will need 6 egg size portions (6 square matzos).

Take one of your neighbors and ask them to take the bread from you and say that they are being Zoche (taking joint ownership) in the bread for the entire building in order to be able to make an Eiruv to carry throughout the building.

You should then take the bread back and say: I am making an Eiruv with this bread, to allow everyone within the building to be able to carry from one apartment to another apartment and from one area to another area within the building for all Shabbosos the year.

If you live in an apartment complex ask a Rov if you can include the entire complex in your Eiruv.

Even if you are not going to need an Eiruv it is mitzva to make one.