Property 'noUiSlider' does not exist on type 'HTMLElement'

This is a road block. What am I doing wrong?

....
/// <reference path="../../../typings/tsd.d.ts" />
var slider:HTMLElement = document.getElementById('slider');

noUiSlider.create(slider, {
    start: +$input.val(),
    step: +$input.prop('step'),
    behaviour: 'tap',
    range: {
        'min': +$input.prop('min'),
        'max': +$input.prop('max')
    },
    format: wNumb({
        decimals: 0,
        thousand: ','
    })
});

// this barfs in TS — error in as title of this post
slider.noUiSlider.on('update', (values, handle) => {
    $input.val(values[0]);
});

// this does too.
<HTMLElement>slider.noUiSlider.on('update', (values, handle) => {
    $input.val(values[0]);
});

My TSD file contains the nouislider typing from https://github.com/retyped/nouislider-tsd-ambient/blob/master/nouislider.d.ts

Error details:

{ [TypeScript error: resources/assets/typescript/common.ts(44,25): Error TS2339: Property 'noUiSlider' does not exist on type 'HTMLElement'.]
    message: 'resources/assets/typescript/common.ts(44,25): Error TS2339: Property \'noUiSlider\' does not exist on type \'HTMLElement\'.',
    fileName: 'resources/assets/typescript/common.ts',
    line: 44,
    column: 25,
    name: 'TypeScript error' }

Thoughts?

Edit: My IDE (PHPStorm) is hinting that there could be an error. That points to lib.es6.d.ts and of course noUiSlideraint going to be there.

Edit (solution):

var slider = document.getElementById('slider') as noUiSlider.Instance;

    noUiSlider.create(slider, {
      //...blah...
    });

    slider.noUiSlider.on('update', (values, handle) => {
        $input.val(values[0]);
    });

Based on the linked d.ts it seems that you need to do:

var slider: noUiSlider.Instance = document.getElementById('slider') as noUislider.Instance;

They don't seem to change the HTMLElement interface, instead they extend it with noUiSlider.Instance:

declare module noUiSlider {
    ...
    interface noUiSlider {
        ...
    }

    interface Instance extends HTMLElement {
        noUiSlider: noUiSlider
    }
}