Plague Year Series

The Plague Year Series is a trilogy of apocalyptic science fiction novels by Jeff Carlson, starting with Plague Year (2007), continuing with Plague War (2008) and ending with Plague Zone (2009). The series shows the aftermath of a nanotech disaster that destroys nearly all warm-blooded life on the planet.

Twenty Minutes Into the Future, a group of scientists are working on a nanotech that will cure cancer by targeting specific cells and dismantling them. Predictably, things Go Horribly Wrong and the nanotech starts dismantling everything. There are two limitations, luckily, that prevent the situation from becoming a full blown Grey Goo apocalypse...first, the nanotech only affects warm-blooded creatures (being powered by their body heat). Two, the nanotech stops functioning in low air pressure. This becomes humanity's only saving grace, as this means that elevations of 10,000 feet above sea level are safe.

Though the nanotech isn't instantaneous (taking several hours to kill a human) it is airborne, and it spreads rapidly. Mass panic happens all over the world as pretty much the entire population of Earth attempts to flee to higher elevations to escape. Anyone not able to reach high ground fast enough succumbs to the plague. In the space of days, five billion are dead. It Gets Worse when the survivors who managed to make it to altitude find themselves without any food or supplies; many more people die of starvation and in-fighting on isolated mountain peaks around the world.

Plague Year primarly follows two character. The first is Cam Najarro, a young ski rat who happens to be at the local resort when the plague strikes. Cam and the other survivors at the resort quickly find their fortune turn to a bitter struggle for survival as food runs out, with starvation eventually leading to cannibalism. When a man named Hollywood arrives, half-dead from the plague but promising better supplies and food if he's followed back to his peak, Cam jumps at the chance to leave the hell of the ski resort. Along with Sawyer, a fellow survivor who seems to be suspiciously knowledgeable about the plague, Cam begins a dangerous journey into the nano-infested lower altitudes, with the hope of reaching Hollywood's camp before their insides are liquified by the plague.

The second main character is a brilliant nanotech researcher named Ruth who was put aboard the International Space Station by the U.S. Government at the first sign of the nanotech plague. Ruth is one of the only remaining scientist with advanced enough knowledge to possibly create a vaccine to the plague, and the ISS is perfect sactuary from the plague. The tattered remains of the government (now set up in Leadville, CO) has alternate plans for how the vaccine will be used, though...

This series provides examples of:

 * After the End: The series occurs after the nanotech plague has already killed the majority of the population. In Plague Zone it is briefly mentioned that the remainder of the human race numbers no more than 500 million.
 * But What About the Astronauts?: Slightly subverted with Ruth, in that she's sent to the ISS specifically to avoid the nanotech plague.
 * The Deadliest Mushroom: After  is nuked in the second book,   avoiding the clouds of fallout becomes a major concern for the characters..
 * Depopulation Bomb: The nanotech not only kills off most of humanity, but every single warm blooded creature below 10,00 feet.
 * Divided States of America: a new American civil war starts between the oppressive new goverment in Leadville, CO  and The Rebels.
 * Freak Lab Accident: The nanotech was originally meant to be a cure for cancer. By the time they realized what it actually did, it had spread beyond anyone's ability to contain it.
 * Gaias Lament: Earth's ecosytem is absolutely ruined by the plague; with the absence of any warm-blooded animals, the surviving reptile and insect populations explode. This causes a massive plant die-off as the insects feed on anything they can find. Without the plants to hold the soil together, massive erosion from rainstorms changes the landscape, destroying towns and roads.
 * Grey Goo: Subverted, in the nanotech only destroys warm-blooded creatures (it only functions because it's powered by body heat).
 * A variation occurs later on with the development of weaponized nanotech called "The Snowflake", which disolves creatures in a matter of seconds but rapidly burns out (so it can be localized and won't spread).
 * Healing Factor: Aside from being intended as a cancer cure, the nanotech was hoped to become this..
 * I'm Melting: The slow fate of someone afflicted with the plague; if you cannot get to altitude quick enough, you eventually die from your body just breaking down (as the microscopic machines dismantle you, bit by bit). The nanotech disolves pretty much everything, except the bones in some cases (which have cooled, and thus can no longer power the nanotech).
 * Inferred Holocaust: Completely averted with regards to the Earth's ecosystem. The author goes to great pains to describe what the realistic consequences of nearly all warm-blooded animals being wiped out would be.
 * The Plague: Although not a plague in the tradtional biological sense, since simply going above 10,000 feet gets rid of it.
 * Mike Nelson Destroyer of Worlds: The various nanotechs in the series were all created by scientists who were trying to do good things (cure cancer, reverse the nano plague, etc).
 * Mind Virus: Explored in the third novel, with a nano-virus that renders its victims similar to mindless zombies (but still very much alive).
 * Mohs Scale of Science Fiction Hardness: Pretty far toward the "hard" end of the scale, with realistic depictions of ecological collapse and nanotech that isn't simply "magic" but has defined and somewhat realistic limitations.
 * Nanomachines
 * No Party Like a Donner Party: Cam's group on the ski resort. Also implied what happens to most the other survivors of the plague, when they run out of food on whatever mountaintop they managed to get to.
 * Phlebotinum Dependence: Since the nanotech will never go away (it only become inert), the vaccine to the nanotech becomes this.
 * : In Plague Zone, where.
 * Scavenger World: Surivors manage to eke out a living by briefly dipping below the altitude barrier to scavenge nearby cities for supplies.
 * The Swarm: Insects are largely unaffected by the plague. With the death of all warm-blooded animals below 10,000 feet, the insect population explodes. This leads to countless dramatic moments where our heroes have to avoid, lead enemies into, and/or run away from horrific swarms of ants, yellow jackets, etc.
 * Twenty Minutes Into the Future: The dates are unclear, but the setting is ostensibly "modern day", with the advanced nanotechnology being the only futuristic part of the setting.
 * Why Did It Have to Be Snakes: Since reptiles are one of the only major animal groups to survive (along with insects), they end up having a population explosion. The characters are thus frequently running into "nests" filled with thousands of snakes.
 * World War III: Pretty much what happens in the sequels, Plague War and Plague Zone, as the remaining governments of the world fight over the limited "islands" of safety.