It's official -- Bornakk wrote on the official forums that Blizzard has increased the chance that a Northrend herb node will yield a Frost Lotus:
The drop rate of Frost Lotus, from herbs in Northrend, has been increased by 50%.This will be a welcome change for many because with the increase in demand for raiding flasks that patch 3.3 brought, the supply of Frost Lotus on many servers has gotten quite low, which increased prices significantly. This change will go live on servers as they restart, so probably next Tuesday for most.
The new drop rate should have an fairly quick effect on the number of Frost Lotuses listed on your auction house, however it always takes a few days of lower sales volumes before the big farmers start to drop their prices and undercut each other.
My advice? Don't buy any Frost Lotus (or derivative flasks) unless you will use them the same day. Wait until the prices go down before stocking up! Also, if you are a herbalist, you can make a quick profit by spending some time farming now, and try to make some sales before the prices drop.