There is internet access in Jomsom, Chame and Manang, but reports are saying that electricity supplies may be affected. The nearest reliable internet access is in Pokhara, but it may take extra time to reach the city at the present time. The rescue effort is ongoing but it's likely that many of the people who are out of contact will have taken shelter in lodges along the route, and may already be en route to places where they can email or call. I wouldn't read anything into a lack of communication at this stage - phone and internet access is limited in the mountains and many trekking routes were unaffected by the disaster.
Ekantipur is reporting that a group of 60 trekkers in missing in a new snowstorm in Upper Dolpo. Details are here.

Meczko - re an early warning system. This should be easily doable, if the Nepali authorities were not so utterly useless - they only thing they seem to be good at is corruption (and nepotism).
Last Oct, when news of Phailin appeared, Roger Ray pointed out, on this forum, that a similar cyclone in 1995 (I think) had headed up to Nepal from India and killed many trekkers (some crowded lodges were swept away in avalanches). Reading Roger's post, I texted (from the UK) the guide I trek with to warn him. He was initially a bit doubtful about the warning, but a couple of days later the Everest region was hit quite badly (though no one killed) - you were obviously there. My guide and his brother, who was also up there, were OK - we exchanged many text messages, except when they were in a place with no coverage (of which there seem to be quite a few, even in the Everest region main trails - somehting to bear in mind if people need a helicopter rescue).
Anyway if "joe public" can pass on warnings from far away, even a half decent "government" should be able to do so. But the Nepali government (politicians and high grade civil servants), plus good old TAAN (I am being very fecitious) are much more interested in playing petty politics and filling their pockets, and looking after thier relatives and cronies.
Thanks, it looks like he started the circuit on the 6th of 7th, so I guess he would have been close, hopefully he hadn't gotten past Manang
I'm just coming back from the Makalu BC trek, only 2 days of bad weather there, not a real problem.

Even in the middle of lowland Europe the weather service is far from accurate despite state-of-the-art equipment and funding. In the Alps it is even less predictable and can change completely within hours, often enough unforeseen. In the himalayas it will be much more difficult to be accurate. People will be complaining bitterly if they miss their flights due to closure of the trek and then it only rains a little. If you only put up recommendations people will ignore it because they think it won´t be as bad / they think they are tough enough / they have no time to wait / the group is carrying on / the guide must get back for his next group waiting in Pokhara. Best would be to increase communication options around the trek even though it is one nice thing that these are the last places on earth where people aren´t staring at their smartphones 24/7 because they are finally offline. But even with the best equipment and best rescue options readily available in a matter of minutes, the Austrian mountain rescue had to take care of 173 fatalities in 2012, 130 of them while hiking or trekking, not climbing, and Austria is only a small part of the alps (source, in German: http://derstandard.at/1363711401223/Bergretter-2012-im-Dauereinsatz).
Ekantipur is reporting that the death toll has risen to 29, with 100 now missing in Upper Dolpo, but 211 people have not been rescued from the Annupurna region - see here for details.
LP authors on the ground in Nepal are reporting that many groups are now turning back from Manang.
If you are trying to reach friends or relatives, the Annapurna Nepal Avalanche & Blizzard Share Info community (here) has created a spreadsheet of missing and rescued trekkers.

I think, in discussions about predicting and informing trekkers about weather, it's important to distinguish between major weather events and more 'typical' weather. It's certainly true that mountain weather is hard to predict - afternoon precipitation, wind/temp changes, cloud cover appearing out of nowhere. For these more 'typical' weather changes, it's not really reasonable to expect anyone to accurately predict this. And because we know this, we recommend everyone to be prepared to handle these unpredictable 'typical' events - waterproof layer, extra warm layers, water/food, compass/GPS/maps, etc.
However, even in mountain conditions, major events such as multi-day storms, cyclones, etc. are usually known in advance. I can't speak well for the Alps as I've only spent a few weeks there, but I do spend a lot of time in the Sierra Nevadas, in the range of 3,000-4,000m on a regular basis, and pretty much every major storm event I can recall in at least the last 10 years were known at least a day in advance. Yes I've been caught out in unexpected rain/snow, but nothing that would overwhelm my typical trekking gear. And because we know we can usually predict these major events, we don't recommend everyone to be prepared to handle them by packing mountaineering boots/crampons, satellite phones, ice axes/shovels, etc.
The Himalayas are obviously much more extreme, so it's understood that there will still be some major events that would be missed, but wouldn't it be nice to be able to inform trekkers of most of the major weather events as they embark on the highest and most dangerous portion of their trek? Esp. if the information was readily available and just lacking an efficient method to communicate it?
This disaster as a case in point - what surprised me so much about this disaster was that, as early as Sun/Mon, I started reading about how this cyclone was going to dump rain on Nepal - on Facebook no less! It's hard to believe that those in larger cities in Nepal were not aware of the coming storm - and a shame that the trekkers on the trail were not able to receive this information before setting off for the higher altitudes of their trek this week...