npm install generate more folders than needed

I've been using ember for a while and when I wanted to install the node dependencies of a project, I just needed to use npm install to create the folder node_modules with all the dependencies (as it's described in http://ift.tt/1PHF3ot).

Since I was using an old version of node I unisntalled node and npm and installed nvm with the versions node v5.0.0 and npm v3.3.6but now, when I try to use npm install to install the dependencies of a project as I used to do before, instead of the dependencies of the package.json file, I get many, many more from things I'm not sure where they come (I think they are dependencies that npm handles by itself in a globally way but now it's adding them to my project locally, but I'm not sure).

Why am I getting all those unknown (for me) dependencies?

Notice that, when I run ember new it generates the correct dependencies in node_modules but if I delete this folder and run npm install happens the same.