Large Blast Markers, they are annoying.

My tyranid army keeps on losing to various armys that employ large blast markers e.g space marines, tau, necrons, imperial gaurd...what can I do?

... Steal your opponent's large blast markers...

But seriously, I wouldn't be the best to ask, being a Fantasy fellow, but I'd say the usual options would be to take them out early (difficult for the Nids, I know), avoiding them (again, difficult), spreading out (fairly annoying), or just giving your opponent too many targets - rushing with lots of units.

I am also not the best person to ask but I think a combination of Digil's last two points (spread-out, too many targets) colud prove helpfull.

Infiltration/Deep-Strike units? Lictors?

Scuttlers work. In my extraordinarily balanced Genestealer army I give them all Scuttlers.

It gives you a 6" move before the game (a scout move).

This means...

6" (scuttle) + 6" (move) + D6" (Fleet, run) = 12+D6" in turn 1. If your opponent moves towards you (though they generally don't) you could even be first-turn charging with anoter +6", to make a possible total of 24". Those turn 1 charges are easy if the game is a deploy-in-quarters varient though, where armies are placed 18" apart.

When doing that crazy first turn rush just watch out for rapid-fire ranges. They can seriously wipe the very big smile off your face in a very short period of time.

Necrons-large blast templates? Only the monolith has that. From my experience of wasting up OOEs nids with my Necrons, the nids fail to deliver in that they don't make it into combat. I'd go for Digls suggestion, or get a million gaunts with no ranged weapons and without numberand use them as a cheap meat shield. Then your badder units could make it.

Or you could sabotage the dice...

no ranged weapons ?

ahem

Gaunts must choose one weapon from list below:
devourer........3/4pts
fleshborer......2/3pts
spinefist.........1/2pts

Alright then, go for the cheap ones.

Not advised. Without number makes them very expensive free points for your opponent. They come back on from your board edge, so will have an epic walk to actually do something.

Spinefists are about as powerful as a pair of staplers at range...

My point exactly. Meat shields aren't meant to be the killing units. at best they should be poor to average close combat units or poor to average ranged units that can keep up or stay ahead of your main army units.

Meat shields are useless against artillery style weapons and isn't that what most Large Blast Marker templates are caused by?

There is a "formation" that Tim invented to counter large blasts. You arrange your squad in to clumps of 2 with 2" separation between each clump, and each clump only next to 2 other clumps (or one if it is one of the end clumps). You can imagine this as a folded up string of sausages each "sausage" being a group of 2 models and the bit between being 2". In this formation a large blast can only hit 3 models (unless they get a Lucky scatter). This formation is much more compact than trying to space out each model 2" apart, and should make your squads much more hardy than simple bunching.

- Now there's the guy to ask.

Interesting. Might have to try that one out myself. Only thing it that lucky scatters have become more common in 5th Ed with the new template scattering rules. I think... Please correct me if I'm speaking out of my ass...

that is true. to be honest I have not played enough games in fifth to tell. But it is still worth trying.