Accepting organizing duties in a year...but waiting for a new position This question is strongly linked to a previous question of mine:

Tenured position to be started very soon…what to do with the old affiliation

Roughly speaking, my situation is the following: I am a non-tenured track researcher who had applied for permanent positions abroad and now I am waiting for notifications (to be known mid-July the latest).

In my present institution we are assumed to make lot of organization duties, and now the head of my research group is pushing me to organize a big conference in July 2016 (big for me means more than 300 people). This means that we should start preparing applications for grants as soon as possible, webdesign, and things like this that take a lot of time. 

The organization of this conference is possibly one of the main examples to my current situation: it seems to me that the only talks we have with my boss are concerning the teaching and organizing things during 2016-2017 (which is definitely very far away of my expectations to be in my present institution).

I know, due to the really good advices in the previous post I linked, that I should keep prudent saying things about my application abroad (namely, do not say a word until something is clearer), but now every day he is coming with this type of questions, and this starts being mentally tiring.

How should I manage this?

A more general question (that would contribute in more general sense to the forum) is the following: while having a non-tenured position (3-5 years), which is the horizon that one may have in order to compromise himself/herself with certain duties (organization, applying for research projects that cannot be moved from a country to another, student advising, teaching duties,...)?

Thank you in advances for the suggestions
It's not so uncommon for a "local" conference organizer to have moved to another institution by the time of the conference, but it's good if there are some actual local conference organizers.  Since you are part of a research group, it seems reasonable that you will not need to be a sole organizer (this wasn't 100% clear from your question).  If you are being asked to be the "primary" organizer, you can still do that remotely, but it also makes sense to ask to instead co-organize it with other people.

So I think the main thing you should consider is: how much do you want to be involved with such a conference, regardless of where you'll be?

Note organizing duties usually count as "professional service" rather than "university service," and organizing conferences can have positive benefits for your career.  If you are doing this as "professional service" rather than as part of your job duties (and it sounds like this is the case since you are getting asked to do it, rather than told to do it), once you make a committment, you should typically follow through.  However, if you do move, then co-organizers are generally pretty understanding that certain aspects are harder for you to do remotely.