diff --git a/core/modules/config/config.routing.yml b/core/modules/config/config.routing.yml
index 0fdb30b..61ff8e3 100644
--- a/core/modules/config/config.routing.yml
+++ b/core/modules/config/config.routing.yml
@@ -7,7 +7,7 @@ config.sync:
     _permission: 'synchronize configuration'
 
 config.diff:
-  path: '/admin/config/development/configuration/sync/diff/{source_name}/{target_name}'
+  path: '/admin/config/development/configuration/sync/diff/{source_storage}/{source_name}/{target_name}'
   defaults:
     _content: '\Drupal\config\Controller\ConfigController::diff'
     target_name: NULL
@@ -15,7 +15,7 @@ config.diff:
     _permission: 'synchronize configuration'
 
 config.diff_collection:
-  path: '/admin/config/development/configuration/sync/diff_collection/{collection}/{source_name}/{target_name}'
+  path: '/admin/config/development/configuration/sync/diff_collection/{source_storage}/{collection}/{source_name}/{target_name}'
   defaults:
     _content: '\Drupal\config\Controller\ConfigController::diff'
     target_name: NULL
diff --git a/core/modules/config/src/Controller/ConfigController.php b/core/modules/config/src/Controller/ConfigController.php
index eeec671..a5039b3 100644
--- a/core/modules/config/src/Controller/ConfigController.php
+++ b/core/modules/config/src/Controller/ConfigController.php
@@ -22,18 +22,18 @@
 class ConfigController implements ContainerInjectionInterface {
 
   /**
-   * The target storage.
+   * The active storage.
    *
    * @var \Drupal\Core\Config\StorageInterface
    */
-  protected $targetStorage;
+  protected $activeStorage;
 
   /**
-   * The source storage.
+   * The staging storage.
    *
    * @var \Drupal\Core\Config\StorageInterface
    */
-  protected $sourceStorage;
+  protected $stagingStorage;
 
   /**
    * The configuration manager.
@@ -56,6 +56,7 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('config.storage'),
       $container->get('config.storage.staging'),
+      $container->get('config.storage.snapshot'),
       $container->get('config.manager'),
       new FileDownloadController()
     );
@@ -64,16 +65,19 @@ public static function create(ContainerInterface $container) {
   /**
    * Constructs a ConfigController object.
    *
-   * @param \Drupal\Core\Config\StorageInterface $target_storage
-   *   The target storage.
-   * @param \Drupal\Core\Config\StorageInterface $source_storage
-   *   The source storage
+   * @param \Drupal\Core\Config\StorageInterface $active_storage
+   *   The active storage.
+   * @param \Drupal\Core\Config\StorageInterface $staging_storage
+   *   The staging storage.
+   * @param \Drupal\Core\Config\StorageInterface $snapshot_storage
+   *   The snapshot storage.
    * @param \Drupal\system\FileDownloadController $file_download_controller
    *   The file download controller.
    */
-  public function __construct(StorageInterface $target_storage, StorageInterface $source_storage, ConfigManagerInterface $config_manager, FileDownloadController $file_download_controller) {
-    $this->targetStorage = $target_storage;
-    $this->sourceStorage = $source_storage;
+  public function __construct(StorageInterface $active_storage, StorageInterface $staging_storage, StorageInterface $snapshot_storage, ConfigManagerInterface $config_manager, FileDownloadController $file_download_controller) {
+    $this->activeStorage = $active_storage;
+    $this->stagingStorage = $staging_storage;
+    $this->snapshotStorage = $snapshot_storage;
     $this->configManager = $config_manager;
     $this->fileDownloadController = $file_download_controller;
   }
@@ -90,8 +94,8 @@ public function downloadExport() {
       $archiver->addString("$name.yml", Yaml::encode($this->configManager->getConfigFactory()->get($name)->getRawData()));
     }
     // Get all override data from the remaining collections.
-    foreach ($this->targetStorage->getAllCollectionNames() as $collection) {
-      $collection_storage = $this->targetStorage->createCollection($collection);
+    foreach ($this->activeStorage->getAllCollectionNames() as $collection) {
+      $collection_storage = $this->activeStorage->createCollection($collection);
       foreach ($collection_storage->listAll() as $name) {
         $archiver->addString(str_replace('.', '/', $collection) . "/$name.yml", Yaml::encode($collection_storage->read($name)));
       }
@@ -104,6 +108,8 @@ public function downloadExport() {
   /**
    * Shows diff of specificed configuration file.
    *
+   * @param string $source_storage
+   *   The name of the source storage to diff against active.
    * @param string $source_name
    *   The name of the configuration file.
    * @param string $target_name
@@ -116,25 +122,26 @@ public function downloadExport() {
    * @return string
    *   Table showing a two-way diff between the active and staged configuration.
    */
-  public function diff($source_name, $target_name = NULL, $collection = NULL) {
+  public function diff($source_storage, $source_name, $target_name = NULL, $collection = NULL) {
     if (!isset($collection)) {
       $collection = StorageInterface::DEFAULT_COLLECTION;
     }
-    $diff = $this->configManager->diff($this->targetStorage, $this->sourceStorage, $source_name, $target_name, $collection);
+    $source = $source_storage . 'Storage';
+    $diff = $this->configManager->diff($this->activeStorage, $this->$source, $source_name, $target_name, $collection);
     $formatter = new \DrupalDiffFormatter();
     $formatter->show_header = FALSE;
 
     $build = array();
 
-    $build['#title'] = t('View changes of @config_file', array('@config_file' => $source_name));
+    $build['#title'] = \Drupal::translation()->translate('View changes of @config_file', array('@config_file' => $source_name));
     // Add the CSS for the inline diff.
     $build['#attached']['css'][] = drupal_get_path('module', 'system') . '/css/system.diff.css';
 
     $build['diff'] = array(
       '#type' => 'table',
       '#header' => array(
-        array('data' => t('Old'), 'colspan' => '2'),
-        array('data' => t('New'), 'colspan' => '2'),
+        array('data' => $source_storage, 'colspan' => '2'),
+        array('data' => \Drupal::translation()->translate('Active'), 'colspan' => '2'),
       ),
       '#rows' => $formatter->format($diff),
     );
diff --git a/core/modules/config/src/Form/ConfigSync.php b/core/modules/config/src/Form/ConfigSync.php
index 7c48dd5..c5f1bb0 100644
--- a/core/modules/config/src/Form/ConfigSync.php
+++ b/core/modules/config/src/Form/ConfigSync.php
@@ -36,18 +36,25 @@ class ConfigSync extends FormBase {
   protected $lock;
 
   /**
-   * The source configuration object.
+   * The staging storage configuration object.
    *
    * @var \Drupal\Core\Config\StorageInterface
    */
-  protected $sourceStorage;
+  protected $stagingStorage;
 
   /**
-   * The target configuration object.
+   * The active storage configuration object.
    *
    * @var \Drupal\Core\Config\StorageInterface
    */
-  protected $targetStorage;
+  protected $activeStorage;
+
+  /**
+   * The snapshot storage configuration object.
+   *
+   * @var \Drupal\Core\Config\StorageInterface
+   */
+  protected $snapshotStorage;
 
   /**
    * Event dispatcher.
@@ -94,10 +101,12 @@ class ConfigSync extends FormBase {
   /**
    * Constructs the object.
    *
-   * @param \Drupal\Core\Config\StorageInterface $sourceStorage
-   *   The source storage object.
-   * @param \Drupal\Core\Config\StorageInterface $targetStorage
-   *   The target storage manager.
+   * @param \Drupal\Core\Config\StorageInterface $stagingStorage
+   *   The staging storage object.
+   * @param \Drupal\Core\Config\StorageInterface $activeStorage
+   *   The active storage manager.
+   * @param \Drupal\Core\Config\StorageInterface $snapshotStorage
+   *   The snapshot storage manager.
    * @param \Drupal\Core\Lock\LockBackendInterface $lock
    *   The lock object.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
@@ -113,9 +122,10 @@ class ConfigSync extends FormBase {
    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
    *   The theme handler
    */
-  public function __construct(StorageInterface $sourceStorage, StorageInterface $targetStorage, LockBackendInterface $lock, EventDispatcherInterface $event_dispatcher, ConfigManagerInterface $config_manager, UrlGeneratorInterface $url_generator, TypedConfigManagerInterface $typed_config, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler) {
-    $this->sourceStorage = $sourceStorage;
-    $this->targetStorage = $targetStorage;
+  public function __construct(StorageInterface $stagingStorage, StorageInterface $activeStorage, StorageInterface $snapshotStorage, LockBackendInterface $lock, EventDispatcherInterface $event_dispatcher, ConfigManagerInterface $config_manager, UrlGeneratorInterface $url_generator, TypedConfigManagerInterface $typed_config, ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler) {
+    $this->stagingStorage = $stagingStorage;
+    $this->activeStorage = $activeStorage;
+    $this->snapshotStorage = $snapshotStorage;
     $this->lock = $lock;
     $this->eventDispatcher = $event_dispatcher;
     $this->configManager = $config_manager;
@@ -132,6 +142,7 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('config.storage.staging'),
       $container->get('config.storage'),
+      $container->get('config.storage.snapshot'),
       $container->get('lock'),
       $container->get('event_dispatcher'),
       $container->get('config.manager'),
@@ -159,9 +170,108 @@ public function buildForm(array $form, array &$form_state) {
       '#value' => $this->t('Import all'),
     );
 
-    $source_list = $this->sourceStorage->listAll();
-    $storage_comparer = new StorageComparer($this->sourceStorage, $this->targetStorage, $this->configManager);
-    if (empty($source_list) || !$storage_comparer->createChangelist()->hasChanges()) {
+    $snapshot_comparer = new StorageComparer($this->activeStorage, $this->snapshotStorage, $this->configManager);
+
+    if (empty($form_state['input']) && $snapshot_comparer->createChangelist()->hasChanges()) {
+      drupal_set_message($this->t('Changes have been made to your active configuration, which might be lost on the next import attempt.'), 'warning');
+
+      $form['snapshot']['heading'] = array(
+        '#type' => 'html_tag',
+        '#tag' => 'h1',
+        '#value' => $this->t('Changes to the Active Configuration'),
+      );
+      foreach ($snapshot_comparer->getAllCollectionNames() as $collection) {
+        if ($collection != StorageInterface::DEFAULT_COLLECTION) {
+          $form['snapshot'][$collection]['collection_heading'] = array(
+            '#type' => 'html_tag',
+            '#tag' => 'h2',
+            '#value' => $this->t('!collection configuration collection', array('!collection' => $collection)),
+          );
+        }
+        foreach ($snapshot_comparer->getChangelist(NULL, $collection) as $config_change_type => $config_names) {
+          if (empty($config_names)) {
+            continue;
+          }
+
+          // @todo A table caption would be more appropriate, but does not have the
+          //   visual importance of a heading.
+          $form['snapshot'][$collection][$config_change_type]['heading'] = array(
+            '#type' => 'html_tag',
+            '#tag' => 'h3',
+          );
+          switch ($config_change_type) {
+            case 'create':
+              $form['snapshot'][$collection][$config_change_type]['heading']['#value'] = format_plural(count($config_names), '@count new', '@count new');
+              break;
+
+            case 'update':
+              $form['snapshot'][$collection][$config_change_type]['heading']['#value'] = format_plural(count($config_names), '@count changed', '@count changed');
+              break;
+
+            case 'delete':
+              $form['snapshot'][$collection][$config_change_type]['heading']['#value'] = format_plural(count($config_names), '@count removed', '@count removed');
+              break;
+
+            case 'rename':
+              $form['snapshot'][$collection][$config_change_type]['heading']['#value'] = format_plural(count($config_names), '@count renamed', '@count renamed');
+              break;
+          }
+          $form['snapshot'][$collection][$config_change_type]['list'] = array(
+            '#type' => 'table',
+            '#header' => array('Name', 'Operations'),
+          );
+
+          foreach ($config_names as $config_name) {
+            if ($config_change_type == 'rename') {
+              $names = $snapshot_comparer->extractRenameNames($config_name);
+              $route_options = array('source_storage' => 'snapshot', 'source_name' => $names['old_name'], 'target_name' => $names['new_name']);
+              $config_name = $this->t('!source_name to !target_name', array('!source_name' => $names['old_name'], '!target_name' => $names['new_name']));
+            }
+            else {
+              $route_options = array('source_storage' => 'snapshot', 'source_name' => $config_name);
+            }
+            if ($collection != StorageInterface::DEFAULT_COLLECTION) {
+              $route_options['collection'] = $collection;
+              $href = $this->urlGenerator->getPathFromRoute('config.diff_collection', $route_options);
+            }
+            else {
+              $href = $this->urlGenerator->getPathFromRoute('config.diff', $route_options);
+            }
+            $links['view_diff'] = array(
+              'title' => $this->t('View differences'),
+              'href' => $href,
+              'attributes' => array(
+                'class' => array('use-ajax'),
+                'data-accepts' => 'application/vnd.drupal-modal',
+                'data-dialog-options' => json_encode(array(
+                  'width' => 700,
+                )),
+              ),
+            );
+            $form['snapshot'][$collection][$config_change_type]['list']['#rows'][] = array(
+              'name' => $config_name,
+              'operations' => array(
+                'data' => array(
+                  '#type' => 'operations',
+                  '#links' => $links,
+                ),
+              ),
+            );
+          }
+        }
+      }
+    }
+
+    $source_list = $this->stagingStorage->listAll();
+    $staging_comparer = new StorageComparer($this->stagingStorage, $this->activeStorage, $this->configManager);
+
+    $form['heading'] = array(
+      '#type' => 'html_tag',
+      '#tag' => 'h1',
+      '#value' => $this->t('Changes to be Imported'),
+    );
+
+    if (empty($source_list) || !$staging_comparer->createChangelist()->hasChanges()) {
       $form['no_changes'] = array(
         '#type' => 'table',
         '#header' => array('Name', 'Operations'),
@@ -171,20 +281,20 @@ public function buildForm(array $form, array &$form_state) {
       $form['actions']['#access'] = FALSE;
       return $form;
     }
-    elseif (!$storage_comparer->validateSiteUuid()) {
+    elseif (!$staging_comparer->validateSiteUuid()) {
       drupal_set_message($this->t('The staged configuration cannot be imported, because it originates from a different site than this site. You can only synchronize configuration between cloned instances of this site.'), 'error');
       $form['actions']['#access'] = FALSE;
       return $form;
     }
     else {
       // Store the comparer for use in the submit.
-      $form_state['storage_comparer'] = $storage_comparer;
+      $form_state['staging_comparer'] = $staging_comparer;
     }
 
     // Add the AJAX library to the form for dialog support.
     $form['#attached']['library'][] = 'core/drupal.ajax';
 
-    foreach ($storage_comparer->getAllCollectionNames() as $collection) {
+    foreach ($staging_comparer->getAllCollectionNames() as $collection) {
       if ($collection != StorageInterface::DEFAULT_COLLECTION) {
         $form[$collection]['collection_heading'] = array(
           '#type' => 'html_tag',
@@ -192,7 +302,7 @@ public function buildForm(array $form, array &$form_state) {
           '#value' => $this->t('!collection configuration collection', array('!collection' => $collection)),
         );
       }
-      foreach ($storage_comparer->getChangelist(NULL, $collection) as $config_change_type => $config_names) {
+      foreach ($staging_comparer->getChangelist(NULL, $collection) as $config_change_type => $config_names) {
         if (empty($config_names)) {
           continue;
         }
@@ -227,12 +337,12 @@ public function buildForm(array $form, array &$form_state) {
 
         foreach ($config_names as $config_name) {
           if ($config_change_type == 'rename') {
-            $names = $storage_comparer->extractRenameNames($config_name);
-            $route_options = array('source_name' => $names['old_name'], 'target_name' => $names['new_name']);
+            $names = $staging_comparer->extractRenameNames($config_name);
+            $route_options = array('source_storage' => 'staging', 'source_name' => $names['old_name'], 'target_name' => $names['new_name']);
             $config_name = $this->t('!source_name to !target_name', array('!source_name' => $names['old_name'], '!target_name' => $names['new_name']));
           }
           else {
-            $route_options = array('source_name' => $config_name);
+            $route_options = array('source_storage' => 'staging', 'source_name' => $config_name);
           }
           if ($collection != StorageInterface::DEFAULT_COLLECTION) {
             $route_options['collection'] = $collection;
@@ -248,7 +358,7 @@ public function buildForm(array $form, array &$form_state) {
               'class' => array('use-ajax'),
               'data-accepts' => 'application/vnd.drupal-modal',
               'data-dialog-options' => json_encode(array(
-                'width' => 700
+                'width' => 700,
               )),
             ),
           );
@@ -272,7 +382,7 @@ public function buildForm(array $form, array &$form_state) {
    */
   public function submitForm(array &$form, array &$form_state) {
     $config_importer = new ConfigImporter(
-      $form_state['storage_comparer'],
+      $form_state['staging_comparer'],
       $this->eventDispatcher,
       $this->configManager,
       $this->lock,
@@ -284,16 +394,16 @@ public function submitForm(array &$form, array &$form_state) {
     if ($config_importer->alreadyImporting()) {
       drupal_set_message($this->t('Another request may be synchronizing configuration already.'));
     }
-    else{
+    else {
       try {
         $sync_steps = $config_importer->initialize();
         $batch = array(
           'operations' => array(),
           'finished' => array(get_class($this), 'finishBatch'),
-          'title' => t('Synchronizing configuration'),
-          'init_message' => t('Starting configuration synchronization.'),
-          'progress_message' => t('Completed @current step of @total.'),
-          'error_message' => t('Configuration synchronization has encountered an error.'),
+          'title' => $this->t('Synchronizing configuration'),
+          'init_message' => $this->t('Starting configuration synchronization.'),
+          'progress_message' => $this->t('Completed @current step of @total.'),
+          'error_message' => $this->t('Configuration synchronization has encountered an error.'),
           'file' => drupal_get_path('module', 'config') . '/config.admin.inc',
         );
         foreach ($sync_steps as $sync_step) {